A typical Facebook post only reaches 16% of friends

"Amongst all the business-related news at FMC, Facebook revealed that the average news feed story from a user profile reaches just 16 percent of their friends. Your actively shared links, photos, and status updates probably reach much higher than 16 percent of your friends, while more inane auto-generated posts about new friendships, wall posts, and articles you read may only be seen by your closest buddies.
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After his Q&A session about ads during the Facebook Marketing Conference, I followed up with Boland, asking if the 16 percent average distribution rate hampered communication. He defended Facebook’s news feed, saying “No, there are pieces of content you create that are interesting, and there’s some that are not.” And the 16 percent doesn’t just apply to users. Business Pages have the same average reach, which is why Facebook is launching its new “Reach Generator” to help marketers buy extra distribution of their Page posts on the ads sidebar, in the web and mobile news feed, and even on the logout page.
The stat from Director of Product Marketing Brian Boland was backed up by VP Chris Cox who said this holds true “in aggregate across all profiles, all types of content, all interactions, all ages, and all demographics.” By reducing the reach of low relevance posts, Facebook leaves news feed space for compelling wedding photos, new job announcements, funny videos, and urgent questions. Still, it means the ambient intimacy of the news feed can’t completely replace the reliability for direct communication."

Source:  TechCrunch, 1st March 2012