I think this question requires a little disambiguation. By "enhance Democratic values" do you mean improve the values themselves or promote the better exhibition of them in reality? Assuming you mean the latter, I think there is an analogous principle that I picked up reading Toynbee. I don't have it in front of me but it was something to the effect that the more military force is specialized the more it promotes authoritarian government as during the medieval knight, and the more common it is the more it promotes democratic rule, as during the frontier rifle. If we view the dissemination of information as a source of power influential in politics then I think the answer might depend on how specialized social media is. In some ways it is quite specialized in the way it is determined which content is displayed and I think this aspect could be over represented by a certain expert class. Also there is the potential for special interests to obtain preferential treatment in that the source of the power is very centralized. This would promote the interests of a privileged class.
I think, worth considering is to what extent democratic values are complimentary to or are juxtaposed to meritocratic values. Perhaps it would be socially salubrious if the obtainment of power within the realm of social media favored whoever was most effective rather than all equally.