The document discusses the 90-9-1 rule of thumb for participation in online communities, which suggests that 90% of members will not post or speak up at all, 9% will participate occasionally, and 1% will be very active regular contributors. However, several data sources presented in the document show participation levels are often lower than this, with some communities having 95-4-1 or even higher levels of inactivity. While the 90-9-1 rule is often cited, the document examines evidence that actual participation ratios vary widely and are often less equitable than this rule of thumb suggests.