What's the fraction of lurkers vs active users?
nostrademons: FictionAlley (Harry Potter fanfiction) was a 100:10:1 ratio - we usually had about 10-20 simultaneous users actually posting on the forums or fanfic sites, 100-200 registered users browsing, and 1000 simultaneous unregistered guests (out of a total registered userbase of about 100k).  This seems fairly typical of most community-oriented sites.Diffle (Flash games hosting) maxed out at about 1200 uniques/month, a dozen or two registered users, and about 6 that actually contributed content or games.  Similar ratios, but fewer registered visitors because people go to flash games sites to play and you didn't need to be registered to play.