A while back JKR posted on her site that yes it really was her in a Harry Potter chat room. She had gone into a chat room and told people who she was and no one believed her! LOL!
She gave different theories on what will happen next in the series and everyone told her she was nuts and how those things will never happen. She said finally she just gave up and started talking Sponge Bob with everyone.
No doubt one of Harry's spells turned SpongeBob gay...