There's been comment here before on the large number of visitors and far fewer posters.

There's an article named Participation Inequality here www.useit.com/alertbox/participation_inequality.html

The gist of it is:

User participation often more or less follows a 90-9-1 rule:

* 90% of users are lurkers (i.e., read or observe, but don't contribute).
* 9% of users contribute from time to time, but other priorities dominate their time.
* 1% of users participate a lot and account for most contributions: it can seem as if they don't have lives because they often post just minutes after whatever event they're commenting on occurs

Just thought it gives a bit of perspective.

zoo

Thanks for posting this link.

there is also a 90/10 rule for p2p-systems:
10 per cent of the users contribute 90 per cent of the music files.