Facebook famously has a lot of users, around 955 million by latest count. But according to new filings with the SEC, 8.7% of those account are not what you’d call really people. THEY’RE MONSTERS AND GHOSTS. Okay, not precisely.

From the BBC:

Duplicate profiles – belonging to already registered users – made up 4.8% of its membership figure. User-misclassified accounts amounted to 2.4% – including personal profiles for businesses or pets – while 1.5% of users were described as “undesirable”.

These numbers stir up new questions about the efficacy of advertising, which is the foundation of the company’s revenue model. The BBC recently created a fake company to analyze the Likes that the company would get and found that it was dominated by dummy accounts probably set up for the purpose of spamming the organization setting up the page and other people Liking it. If you’re a company, you might not mind getting all those Likes because it means you appear more powerful. So everyone’s happy except Facebook because no one is exchanging any dollars.

The other concern about illegitimate accounts is that they skew the numbers of actual consumers so it kind of runs up the numbers of who’s out there.