I would have no problem with paying $5-10 per month for each of Google, Facebook, and Twitter, as they are currently constituted (although as long as I'm paying

I would have no problem with paying $5-10 per month for each of Google, Facebook, and Twitter, as they are currently constituted (although as long as I'm paying money, let's say that they are 100% ad free). The trouble is, if they charged this, then a great many people who add value to my experience of Facebook and Twitter would drop away, reducing my own experience of the networks and probably making me question whether it was worth the money for me. (Google is a separate question because the network effect is less of an issue for web-apps, email, calendar, and so forth - they are still valuable for my personal use even without the sharing and networking features.) Many people already pay similar prices for the higher end versions of Dropbox or Evernote, but again the "web app" vs "social network" factor comes into play. It doesn't benefit me as a Dropbox or Evernote user if more people use Dropbox or Evernote, except in very indirect ways, whereas it does benefit me as a Facebook user if my friends all use Facebook.