Facebook has confirmed that it's currently in the process of deleting fake accounts and Page likes as it implements site integrity improvements which it announced last month.
Facebook confirmed the news with TechCrunch after many Facebook business pages saw fan numbers drop by tens of thousands. They found that Zynga's Texas HoldEm Poker fan page dropped by 96,000 yesterday, previously having steady growth. They also spoke to one business owner who told them that he saw his fans drop by 1,300, taking it down to 5800. Even pages of celebrities have been have been affected, with Eminem's fan Page dropping of 15,420 fans and Rihanna's by 22,198 fans.
Speaking on the matter Facebook said,
On average, less than 1% of Likes on any given Page will be removed.
This is if the page has abided by Facebook's terms and hasn't been purchasing Likes from dodgy websites, which are often run by hackers who create thousands of fake accounts, which can be purchased to make your Page appear more popular than it actually is; businesses have been known to do this to appeal more to potential advertisers.
Hopefully Facebook can keep on top of fake accounts so that it can regain some credibility. With stock dropping, Facebook needs to do everything it can to make investors happy.