Notably, the main function of the signup fee is to throttle growth of the userbase by eliminating most of the lazy driveby traffic, not to generate cash. In that respect, we could be charging $1, or in theory even "charging" some non-fee annoyance, and probably get about the same effect. But $5 is a nice round number -- enough to be a tiny moment of consideration in a web where membership fees for commenting aren't the norm, but not so much that it's going to cause almost anyone with a reasonably sincere interest in the site or the community from making that investment. And so $5 it is.

And while we absolutely don't spite the income from the signups -- it's a nice side effect of the signup-throttling process and helps with costs some -- it's really not nearly enough to cover payroll for three full time mods and a full-time programmer/developer. The bulk of our revenue is from ads running in the archives.

Well, that and their top notch moderators! Jessamyn is exceptional at breaking up arguments, for example.

Metafilter is quite an outlier in terms of online communities that have survived, thrived, and kept a high signal-to-noise ratio.

A $5 registration fee is one of the things that killed kuro5hin.org. God, I miss k5.