Facebook came to their senses Thursday and have turned Beacon to opt-in. Previously, Beacon was an opt-out program and difficult to opt-out of at that.

Facebook users will be prompted to allow “stories” from participating sites before the first story is published. This prompt now happens on login. If the user does nothing with the prompt, the story will not be published.

Facebook is still storing the data and it is still accessible to advertisers, but at least it won’t be published to your friends. Opt-in on the partnering sites would be nice, but I don’t think it is likely to come.

A related note, Coca-Cola was under the impression that Beacon was supposed to be opt-in all along. When they found out that it wasn’t they backed out of the program before launch.