In a with the U.S. Securities and Exchange Commission, Facebook reported that of their 955 million monthly active users, approximately 83 million are not legitimate.

The company reported that people with more than one Facebook account, which is against the site's policies, amount to 4.8% of their monthly active users. They also noted that "false accounts," which include misclassified accounts and accounts set up for, say, spamming, account for 3.9%.

That adds up to 8.7% of Facebook's user base - or 83 million users.

Olds said every social network has a certain percentage of abandoned accounts, fake users, and accounts that exist only to game the system. It's unavoidable.

"But even though this is a fact of life, it's an embarrassing fact of life for social network providers and one that they'd rather not talk about," he added. "What's troubling is when advertisers begin wondering how many of their clicks are from real users and how many might be from fake accounts."