Craigslist appears to have surrendered in a legal fight over erotic ads posted on its website, shutting down its adult services section Saturday and replacing it with a black bar that simply says "censored."

It's not clear if the closure is permanent, and it appears to only affect ads in the United States.

Craigslist has been caught for years in a murky legal fight that centers on how much responsibility the company bears for its ads, said Jonathan Zittrain, professor of law and computer science at Harvard University.