Facebook has been enmeshed in ongoing controversy about who owns user profiles and posts. But there’s really no question — Facebook owns it all in the same way that NBC owns time on its network affiliates and programming, or the New York Times owns advertising space in its print and online editions. The difference is that, unlike mass media of the past, social media sites have often been created based mainly on content from users, not employees.

Recently, I was reading a thread on the leading poker community site, Two Plus Two. The title was “Books on Tells” and the poster was asking other users for reading suggestions. As the co-author of a book on the subject, I identified myself and gave a one paragraph description of the book. Within an hour or so my post had been erased from the thread and I’d received a warning against “self promotion”.

Two Plus Two is a well known publisher and direct seller of poker books. As a media company, they have a clear right to remove posts from authors who aren’t part of their company. If I want to mention my book, I can buy a banner ad, after all. But on the social side, where virtually all of the site’s content is still created by users, it’s clearly of value to allow any relevant author to answer posters asking about books.

It’s a new tension, something the New York Times or TV networks never had to deal with. And I suspect managing it well for both users and social media companies is going to require a set of rules that are only starting to be written.