I agree that advertising should be nationalised and Facebook is a particularly good target.
Advertising makes capitalism more centralized; whoever has the biggest budget gets all the customers.
Having worked for both big corporations and small companies in the tech industry, I'm certain that big corporations are less efficient overall; I think that they are successful in spite of their innefficiencies because of their advertising power.
Centralization reduces the number of people who have wealth (increases inequality); there are so few of these people and their money is in such high demand (and they have so much of it) that they are effectively incapable of investing it efficiently - Their investing bandwidth is all used up (they are spammed-out with investment opportunities).
If wealth was more spread out, more people could be investors and they would have more time to really think through and consider opportunities and because they would have less money on an individual basis, they would be much more careful about their investment decisions.
Centralization reduces the number of people who have wealth (increases inequality); there are so few of these people and their money is in such high demand (and they have so much of it) that they are effectively incapable of investing it efficiently - Their investing bandwidth is all used up (they are spammed-out with investment opportunities). If wealth was more spread out, more people could be investors and they would have more time to really think through and consider opportunities and because they would have less money on an individual basis, they would be much more careful about their investment decisions.