A BBC investigation suggests companies are wasting large sums of money on adverts to gain “likes” from Facebook members who have no real interest in their products.
It also appears many account holders who click on the links have lied about their personal details.
A security expert has said some of the profiles appeared to be “fakes” run by computer programs to spread spam.
Facebook said it had “not seen evidence of a significant problem”.
“Likes” are highly valued by many leading brands’ marketing departments.
Once a user has clicked on a link the company it belongs to can then post content on their news feed, send them messages and alert their friends to the connection.