A woman shoots a video of the sign at the entrance to the Facebook main campus. AFP/Robyn Beck
According to Pagedata, many of the site's most 'liked' pages suffered large drops in numbers on Wednesday.
The move came after it had emerged that 8.7 percent of its users of
the site are not 'real'.
It was claimed that many were set up by spammers who use them to artificially make pages appear more popular, the BBC reports.
Technology news site The Verge, citing Pagedata's statistics, said that some of the most popular pages on Facebook had suddenly shed significant numbers of users.
The page for Texas HoldEm Poker, one of the site's most popular, shed 96,317 "likes" on Wednesday, compared with net gains of about 20,000 each day for the previous month.
According to the report, other prominent pages also saw a drop in numbers, including those of pop singers Rihanna (-28,275), Eminem (-15,420) and Lady Gaga (-34,326).