Have you seen Jakob Nielsen's Oct 9 "Alertbox" on participation in online communities?
From the summary: "In most online systems, 90% of users are lurkers who never contribute, 9% of users contribute a little, and 1% of users account for almost all the action."
I found the information particularly interesting, and intend on using it in a couple of work-related efforts, and wanted to share it with LL. There are several points which I feel applicable.
The column is on his site at www.useit.com.