95 percent of readers don’t contribute
5 percent contribute sometimes
.01 percent contribute frequently

Of the 55 million people online - 5% blog.

Jakob Neilsen looks at participation inequality online.

This type of research has been done for years, starting with Compserv, Usenet, Email lists, and moving into wikis, blogs and commercial sites.

We lurk.

Summary:
In most online communities, 90% of users are lurkers who never contribute, 9% of users contribute a little, and 1% of users account for almost all the action.

All large-scale, multi-user communities and online social networks that rely on users to contribute content or build services share one property: most users don’t participate very much. Often, they simply lurk in the background.

He looks at the pro and con of participation equality, and suggests ways to make things easier for lurkers to participate, including good design.