[tfederman]

I'd like to see a social news site that costs something like $25-50 to join. Enough to keep out kids, spammers, and trolls, but not enough to keep out serious adults.

[MiddleEndian]

Although I am not a member, Metafilter does this with a $5 cost.

[walterbell]

Were you thinking of a one-time fee or annual?