Jakob Nielsen anno 2006 on the 1:9:90 rule of social media:
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.
In contrast, a tiny minority of users usually accounts for a disproportionately large amount of the content and other system activity. This phenomenon of participation inequality was first studied in depth by Will Hill in the early ’90s, when he worked down the hall from me at Bell Communications Research.
(…) it fails to recognise the wider range of activities and behaviours that people can now undertake in modern online Web 2.0 environments. (…) Proclaiming the 1:9:90 rule, therefore, without an understanding of the variety of roles, behaviours, the relationships between them, and the actual statistics, dooms us to a view of the world that social media will only be attractive to a very small proportion of citizens online. But given there are 11.2 million Australians currently online (out of 16.4m), and a whopping 8.5 million who do use social media at least monthly, I think the future is rosier than this 20 year old rule would otherwise suggest.