Via DMN/Allindstrom

How many fake accounts are crawling among your Facebook fans? This isn’t an estimate or research finding, it’s a number confirmed and admitted by Facebook. According to details disclosed in its first financial filing, Facebook estimates that 83 million accounts are total fakes, dupes, or otherwise questionable ‘misclassifications,’ a number that collectively works out to 8.7 percent of the entire Facebook population.
Facebook now claims a total of 955 million monthly active users (MAUs) worldwide, of which (according to the company):
(1) 14.3 million (or 1.5%) are ‘undesirable’
“…user profiles that we determine are intended to be used for purposes that violate our terms of service, such as spamming.”

(2) 22.3 million (or 2.4%) are ‘user misclassified’
“…where users have created personal profiles for a business, organization, or non-human entity such as a pet.”

(3) 45.9 million (or 4.8%) are ‘duplicate accounts’
“…an account that a user maintains in addition to his or her principal account.”

And, realistically, Facebook is probably bumping its topline MAU while downplaying its problematic percentages. Actually, there’s another issue that wasn’t addressed by Facebook: non-spamming fake accounts, created by firms that sell phantom friends. That goes for businesses, bands, or just desperate people needing to inflate their friend counts. Sounds ridiculous, except that we’ve come in contact with an entrepreneur who created just that company after getting ousted from his startup. And he has plenty of competition.
This could be far worse than we think, and the latest news seems like another headache in a growing hangover. Just last week, music startup Limited Run estimated that 80 percent of its ad clicks came from bots (that they were paying for). And earlier, a BBC technology correspondent tested the waters by creating a fake business account, Virtual Bagel, only to find that a majority of likes were coming from fake accounts from the Middle East and Asia.
The list goes on and on, which might explain why shares of Facebook dipped below the $20-mark for the first time in trading on Thursday.
SEC filing, p.24