Just recently when Facebook announced its quarterly earnings, it told that the number of accounts on its social network had increased to 955 million.

Now the social networking giant has revealed that around 8.7 percent of them are fake. This number equals to around 83 million. This is a big jump from the 6 percent or 42 million fake accounts Facebook had just 6 months ago in February.

This number actually includes those accounts as well which were created for any pet, business and multiple accounts by any single user.

To make the data clear, Facebook has classified the information of fake accounts into three groups: duplicate accounts, mis-underclassified accounts and undesirable accounts.

Here is the official statement:

“We estimate that “duplicate” accounts (an account that a user maintains in addition to his or her principal account) may have represented approximately 4.8 percent of our worldwide MAUs(Monthly Active Users) as of June 30, 2012.

We also seek to identify “false” accounts, which we divide into two categories: (1) user-misclassified accounts, where users have created personal profiles for a business, organization, or non-human entity such as a pet (such entities are permitted on Facebook using a Page rather than a personal profile under our terms of service); and (2) undesirable accounts, which represent user profiles that we determine are intended to be used for purposes that violate our terms of service, such as spamming.

As of June 30, 2012, we estimate user-misclassified accounts may have represented approximately 2.4 percent of our worldwide MAUs and undesirable accounts may have represented approximately 1.5 percent of our worldwide MAUs.”

This is a problem for Facebook because advertising is only successful on real user’s accounts so fake users aren’t really helpful. And still, the situation isn’t nearly as worse as Twitter, where it is said that 65 percent of an average user’s followers are fake.

In a related news, amid Fake accounts flap – company’s share price had dipped down to USD 19.90 per share (or USD 45 billion in total value – down from USD 110 billion at the time of IPO) on Friday, which has recovered back a little to settle at USD 21 today.

Facebook is facing tough time in user growth and monetization on mobile interfaces, a challenge that has surfaced and impacted the face value of company’s share to slip down to USD 20 from USD 42 at the time of going public.