A couple of years ago, Connie Crosby mentioned on Slaw (third comment) that she had been surprised to discover that when she 'Liked' a page (by joining a 'fan club') devoted to a product, her name later appeared in advertisements for that product on her Facebook friends' pages.
A number of others appear to have been not only surprised but offended at this practice. They brought a class action against Facebook for the practice, an action now settled for $20 million. Whether Connie gets a share of that, I can't say. Probably not enough to fund a bottle of Canadian Club, even if she still likes it.
Has FB changed its ways, or just put a clearer notice on its site that it can do this kind of thing with products we 'Like'?
[h/t Adam Vereshack]