Patentability of a specific method of web content filtering



My friend is the creator and vendor of a web content filtering software. His clients are ISPs who then offer this service to their customers. Recently his clients received a very threatening "cease and desist" letter from another ISP, operating in the same space, claiming that he is using technology patented by them.

Understandably, this creates an extremely stressful situation for him, endangering his livelihood, etc.

The patent in question is IL225819A. English language patent details, Claims, Sketches.

To quote from the first claim:

1. A method for on- line filtering a presentation comprising:

a) identifying a structure in the presentation;

b) detecting an undesired content in said structure;

c) determining a domination of said structure by said undesired content, and

d) disabling a portion of said structure according to a result of said determining.

According to my understanding of the text, they seem to be patenting a technique that any mediocre software developer would come up with after 2 minutes of thought. Additionally, they seem to be patenting something that is already widely done e.g. by ad-blockers. I am wondering what the validity of such a patent claim is.

Does anyone see the "Inventive step and non-obviousness" of this technique?

Edit: Naturally, I definitely will not act based solely on advice from the internet, I am however interested in opinions as to whether a software patent such as this is to be regarded as the actions of a patent troll and be fought against. Can anyone weigh in with examples of similarly simple software techniques that have nevertheless been upheld by courts (anywhere worldwide)? Is this patent relying upon the fact that nobody in the patent office seems to have much familiarity with web development? Or am I misunderstanding the world of software patents?


Posted 2019-02-16T18:30:12.287

Reputation: 41

What country are we dealing with? – Eric S – 2019-02-17T00:18:22.430

It appears that patent has been granted in US and Israel only, from which jurisdiction did your friend recieve the letter. – RishiM – 2019-02-17T01:46:47.963

Israel. However I specifically left the country open since I would like to get a feel for what would count as an "inventive step" in any country. Would there be sufficient grounds to contest this patent as being an insufficient "inventive step" in any country? – yossizahn – 2019-02-17T06:59:28.010

An Israeli patent only applies to Israel any not any other country. – Eric S – 2019-02-17T15:47:36.513

@EricShain, I am seeking more general enlightenment as to why this patent may be considered by anyone a sufficient "inventive step". This question intentionally wasn't asked in respect to any specific country's laws. – yossizahn – 2019-02-17T17:03:11.873

@RishiM_IPR What US patent is associated with this? – Eric S – 2019-02-17T21:31:27.860

Do we know that this claim comes from the actual granted patent and not an application? Claims in applications are often ridiculously broad. – Eric S – 2019-02-18T20:38:30.920

@EricShain, the linked documents are the text of the actual granted patent. – yossizahn – 2019-02-18T20:53:53.397

Google links to litigation case(s) from darts-ip. My mobile internet doesn't load them atm, but you should have a look at that. – DonQuiKong – 2019-02-18T21:03:39.513



Like any patent, one has to study the claims to know what is protected by the patent. In the case of the linked Israeli patent, I can't read the patent so there is no way to comment on the claims.

As to patentability in general, a patent needs to be novel, non-obvious and useful. Novel means no one has publicly described the invention in the past. Non-obvious means it isn't something someone skilled in the field would find straightforward to do. That said, one really has to study a patent's claims before deciding it is obvious. Many people read the abstract and decide that a patent is covering the world only to find that the claims are exceedingly narrow.

I did a search for patents by the two listed inventors and did find a US patent with the same title: US9529896B2. The first claim on this patent is:

  1. A method for on-line filtering of undesired content from a presentation built from a source code and for displaying the filtered presentation to a user comprising:

    a) identifying a plurality of structures and a plurality of substructures of at least one structure of said plurality of structures in the source code; said at least one structure having a beginning marked by a first marker and an end marked by a second marker; each substructure of said plurality of substructure having a respective beginning marker and wherein each said respective beginning marker is located between said first marker and said second marker and wherein each of said plurality substructures beginning with said respective beginning marker ends with a respective end marker;

    b) detecting the undesired content in said plurality of substructures;

    c) determining at least one substructure dominated by said undesired content;

    d) disabling said at least one substructure according to said determining; said disabling resulting in a a sanitized structure, without the undesired content;

    e) removing said sanitized structure from said presentation when said sanitized structure does not correspond to said structure such that displaying said sanitized structure in the presentation would make the user aware of said disabling and arouse a curiosity of the user of said presentation towards a said undesired content;

    f) sending said source code including an outcome of said disabling and said removing; to an output device for rebuilding and display to the user;

    g) performing a first action when a combination of a first word and a second word is detected between said respective beginning marker and said respective end marker of a single substructure of said plurality of substructures: and

    h) performing a second action different from said first action and when first word is in said single substructure and said second word is not in said single structure and said second word is in another substructure of said plurality of substructures.

Now this claim as well as the other independent claim (7) is fairly long. Remember, to infringing a claim, you need to implement each and every step within a claim. At this point, you've received the "cease and desist" letter so you really shouldn't just decide to ignore it based on advice from the internet. After all, I don't know what you've implemented in your code, I'm not particularly skilled in this field and even if I were, I am not a lawyer. I sincerely suggest you consult with a patent attorney.

Eric S

Posted 2019-02-16T18:30:12.287

Reputation: 7 963

@yossizahn the claim granted in US is narrow when compared to the claim of IL, please look into the prosecution history of Israel patent at following link most of the data is in Hebrew, so I could not interpret which prior art is considered in evaluating inventive step .

– RishiM – 2019-02-18T06:49:49.033

@EricShain, I have updated the question with links to the (English language) Israeli patent. You will notice that it is considerably broader than the US version. – yossizahn – 2019-02-18T07:56:50.630

@RishiM_IPR, Even considering the narrower claims of the US patent, it seems to me - as someone familiar with web development - that it is a very vague and long-winded way of describing exceedingly simple and basic techniques, certainly not worthy of being called an "invention". Do I misunderstand the "inventive step" required for a patent? – yossizahn – 2019-02-18T08:21:10.493

@yossizahn The patent on current date may not look like an invention but, could that be called an invention at priorty date ?? i.e., at june 2011 could that web filter be designed by ordinary programmer. If the same filter could be designed by any programmer with ordinary skill on that date of priority then there is no inventive step. More over it appears there is an application for revocation of patent at IL office. – RishiM – 2019-02-18T10:28:49.110

@RishiM_IPR "at june 2011 could that web filter be designed by ordinary programmer" I think that it most certainly could have been. "More over it appears there is an application for revocation of patent at IL office" I am aware of this, but am not in contact with the lawyers involved. Is there any stipulation that requires the examiner responsible for granting patent to have a previous familiarity with the subject matter of the patent (web development, in this case)? – yossizahn – 2019-02-18T11:25:18.920

Usually the examiner assigned would have the the knowledge of the domain. – RishiM – 2019-02-18T13:01:09.103

I have edited the question to include the primary claim. – yossizahn – 2019-02-18T16:47:04.630

@yossizahn I agree that that claim (and also the dependent claims) seem to cover basically every ad-blocker. However, I dont know when the first unobtrusive ad blockers became common. You'd have to find one pre 2011. And it would probably have to do everything from the dependent claims too because you can't leave any infringed claim valid. – DonQuiKong – 2019-02-18T21:13:21.477

@DonQuiKong, There is also the concept of HTML Sanitization which was definitely well know and practiced long before 2011.

– yossizahn – 2019-02-18T21:30:37.760


This answer is purely about inventive step in general:

Let's take claim 1 from the question as an example: (please note: I didn't read the specification so this is purely based on the wording of the claim, it might not concur with the correct interpretation of the actual patent claim which needs to be interpreted in light of the specification!)

  1. A method for on- line filtering a presentation comprising:

a) identifying a structure in the presentation;

b) detecting an undesired content in said structure;

c) determining a domination of said structure by said undesired content, and

d) disabling a portion of said structure according to a result of said determining.

Now, suppose you have as prior art the html sanitization you mentioned in a comment. According to my understanding, html sanitization does the following:

  • Identify bad html tags (e.g. <embed>) and their endings (e.g. </embed>).

  • remove the tags and their content.

So, what does that mean for claim 1 above?

We seem to fulfill a) by identifying a structure starting and ending with html tags.

We also seem to fulfill d) by removing the structure completly because "completly" is also "a portion". However, completly is only a small subset of "a portion", so there might be an easy way of getting around some prior art like that by amending the claim to say "a portion less than 100%" or something like that. It might even be that it says "a portion is less than 100% of the structure" in the description, invalidating this prior art.

But suppose we actually fulfill steps a) and d) completly. Then the prior art "html sanitization" is not destroying novelty because it does not teach all the elements from the claim (namely: b) and c) are missing).

So, inventive step. We need another document that allows the person skilled in the art to reach the invention.

I'll make one up. Suppose we have a publication about identifying ads in html code. It identifies html structs like <embed> </embed>, searches the content for words like viagra (greetings to the spam detecting bots at SE ;)) and determines if the structure is mainly filled with said undesired content by, say, language analysis. It then determines that the structure is an ad.

This reference teaches a), b) and c). It identifies a structure (html tags), detects an undesired content ("viagra") and determines domination of the structure by said content (checks if the text in the structure relates mainly to viagra).

Combining the references the person skilled in the art could see the advantage of removing html tags with a greater precision by detecting if they contain ads. The person skilled in the art could then reach the invention by combining the two documents, meaning the claim is not inventive over the prior art.

Disclaimer: One could argue against that by saying that html sanitization and ad blocking don't serve the same goal because removing all possibly problematic structures is more secure than removing only some so the person skilled in the art wouldn't combine the references. That argument might or might not be enough to prove inventive step, but it would at least pose some danger to the argumentation. So this isn't a clear cut case.

The above used goes d'accord with pretty much all standard methods for determing (missing) inventive step in the US, Europe and many other places. You need two combinable documents teaching every single step in a method or every single limitation in a system.

You can also use basic knowledge of a person skilled in the art (e.g. web developer), but you need to prove that knowledge. So if you have a textbook saying "Identified ads should be removed from a html site for user convenience." (step d)) you might use that to say my made-up source (steps a) - c)) in combination with the knowledge of the person skilled in the art leads to the claimed method making it obvious / non inventive.


Posted 2019-02-16T18:30:12.287

Reputation: 5 637

for remove <embed> in a html tree, you must detecting an undesired content in said structure;, no? and what do you think the intention of the step c) ? – dovid – 2019-02-19T14:12:28.363

1@dovid not at all, you can just remove every single instance of <embed>. In that case the structure would be "undesired", making no assumption about it's content. I assumed step c) would be something like trying to remove only the innermost elements of the html tree, not all elements containing ads (which would be easiest achieved by removing the complete page) for example. – DonQuiKong – 2019-02-19T14:18:43.550

1@dovid if you say the "structure" is the html tree and the "undesired content" is the html tag <embed>, then you would be fulfilling steps a), b), d) of the method by html sanitization because you are detecting unwanted content in a structure and removing a portion of that structure. Which I didn't think of previously. However, that's exactly why one needs to read the specification. It might be a valid interpretation, it might be an invalid interpretation. This answer is supposed to show how inventive step works, not to be an actual evaluation of the patent or the prior art. – DonQuiKong – 2019-02-19T14:22:16.787

Thanks for your detailed explanation. If I'm understanding you correctly, an "invention" doesn't need to show a large (or even small) amount of creativity. It is sufficient to "invent" a technique in which not every single step of it can be proven to have been known priorly. Oh well. – yossizahn – 2019-02-21T13:22:17.713

@yossizahn even more, generally the steps need to be known from 2 documents (apart from a few exceptions, but let's not go to deep). But then, inventing a completly new step in a method or a completly new way of doing something is inventive, isn't it? Think about it, every invention is a combination of known stuff. So patent law just asks "was it obvious to combine the known things in exactly that way?" – DonQuiKong – 2019-02-21T13:59:12.917

1@yossizahn Think about it the other way around - suppose the patent holds as inventive because it was actually the first adblocker working that way. If it was so obvious, why didn't anyone else do it before that? In hindsight, isn't any programming exercise "obvious" after you have the solution? There is no program someone else couldn't come up with after knowing exactly what it does and how it works. You get a patent for beeing the first one to think of (or at least describe) something. If it isn't viable, the market won't care about the patent. And if it is, you did invent something useful – DonQuiKong – 2019-02-21T14:04:07.483

@DonQuiKong, most of software development is about creatively solving problems. And every software developer everywhere has "invented" fairly obvious methods to solve a problem, and those methods may not have previously been documented, It's sad that one vendor can patent the obvious solution just because nobody documented the approach previously. – yossizahn – 2019-02-21T14:05:38.613

1@yossizahn that's not quite how it works. Let's look at the last program I wrote. 3D knapsack thingy for packages. Whatever, but it works by slicing the volume, doing a whole lot of assumptions, which in that combination nobody else has done, and getting a solution as a result. Patentable? Maybe. But what would that patent be? Knapsack by slicing volume? nah, that's known. Knapsack by slicing volume and x, y, z as assumptions? Maybe. But that would be trivially easy to circumvent too. Just change assumption z to assumption z1. The scope of the patent corresponds to the size of the invention. – DonQuiKong – 2019-02-21T14:18:06.727

If however x, y, z would be the only way of doing this and everyone else would have to do it that way and they weren't described previously, then I invented something i can make money with. But then, it either wasn't that trivial or someone else would have described it prior to me, or nobody has tried solving that problem. – DonQuiKong – 2019-02-21T14:19:21.560

"or nobody has tried solving that problem", I think that's the case here. It's a specific domain that nobody had entered before. (web content filtering on a sub-page level as opposed to the regular - either block entire page or allow it). However, were any competent programmer to be presented with the problem he would most likely come up with an identical solution. – yossizahn – 2019-02-21T17:24:39.687

Suppose a class of puzzles where each puzzle has an obvious (for humans) solution. An infinite number of these puzzles can be generated, each puzzle being solved by a fairly obvious series of steps. Additionally suppose there was no generic algorithm to generate these solutions. Would it be possible for a company to generate many of these puzzles, solve each one, and then patent the solution? or would we consider this class of puzzles as a solved problem since the solutions are always obvious and easy to arrive at? This may be an analogy for the world of software development. – yossizahn – 2019-02-21T17:33:42.330

1@yossizahn findig a problem nobody has thought of is an invention too. Defining the problem often yields the solution. But ex post, after the fact. However, finding the problem, which in this case was a really lucrative one, wasn't obvious. – DonQuiKong – 2019-02-21T20:58:28.950

1@yossizahn I understand what you mean, but everything is obvious if you ask the right question. Then there would be no patents. Asking the right questions is part of the process. – DonQuiKong – 2019-02-21T20:59:40.190