I think paid barriers to entry just amplify the positive or negative effects of other administrative measures; in and of themselves, all they do is reduce the r

I think paid barriers to entry just amplify the positive or negative effects of other administrative measures; in and of themselves, all they do is reduce the rate of people coming in without much affecting its make-up. It doesn't even work that well for filtering out teenagers any more with the advent of prepaid gift cards (and before that they could just ask the 'rents to stump up the cash anyway). I say that paid barriers don't do that much good or bad themselves based on the fact that on MeFi they seem to have been an asset whereas on, say, Something Awful they seem to've just turned the place into an echo chamber, and on Kuro5hin all it's done is drive the site further into stagnation. Paid barriers aren't risk-free either; it makes account gaming even more fun and makes your site a juicier target for attacks, especially if it means you end up storing people's personal details.