From Charles Arthur here is the 1 percent rule:

It’s an emerging rule of thumb that suggests that if you get a group of 100 people online then one will create content, 10 will “interact” with it (commenting or offering improvements) and the other 89 will just view it.

Mindy McAdams has more.

I’ve been involved in user-generated content for a decade at least, and while I’ve never had hard stats, what Arthur presents rings true. Most e-mail discussion lists, forums, virtual communities are populated primarily by lurkers. There is usually a core of heavy contributors, a second tier of people who react to the contributors, and a large group of everybody else. Roles may change over time or from time to time, but the tiers of participation remain fairly consistent.

At one time, I speculated that lurkers were mostly newbies and would learn to be participants and contributors. But more than a decade of the Web has passed, and the proportion of lurkers to contributors remains consistent. Obviously, this isn’t a matter of newness or technical savvy. It’s an issue of personality. Some people will always be lurkers.

That doesn’t mean that all lurkers are always lurkers, or that contributors don’t change roles in other venues, but that experience does not necessarily change habits.

The big challenge for any would-be social network, or virtual community, or participation-based initiative (you pick), is how you entice the 1 percent to get the ball rolling, because without the 1 percent, you don’t get the 10 percent, and hence there is nothing there for the 89 percent.

There is some knowledge and skill involved, but also a lot of luck.