90-9-1 Rule
1% Rule · Participation Inequality
90% of any given Internet community only view content, 9% edit, and 1% create. Said another way, 1% are participants while 99% are lurkers.
Origin
Usability researcher Jakob Nielsen published "Participation Inequality: Encouraging More Users to Contribute" in 2006, crystallizing the 90-9-1 split as a rule of thumb for online communities. The underlying pattern had been observed earlier by Will Hill at Bell Labs in the early 1990s, who studied participation rates in early internet forums. The distribution follows a Zipf curve, and Nielsen argued that lowering barriers to contribution was the key to shifting the ratio.
Everyday Use
Check any online forum, subreddit, or group chat: a tiny fraction of people post most of the content while the vast majority just scroll. If you've ever thought "somebody else will answer that," you're in the 90%. The same pattern appears in open-source projects, wikis, and even workplace Slack channels.