Yahoo Instant messenger

I have a friend that is being cyber stalked. The stalker was at one time on her friends list in Yahoo Instant messenger. He has told her that he has a utility that tells him when she is online with Yahoo IM and even who she is chatting with. I told her I didn't think this was possible, and was he perhaps using deductive reasoning instead. She assured me that she had tested him, and he indeed knew who she was chatting with, and even though she was in invisible mode, he knew when she was online. Being that this is a violation of the TOS of yahoo, I urged her to report it to yahoo, as a security issue. He was booted from yahoo, but the next day he was back with the same nick. He is a script kitty and a hacker of some sort, so he gets around yahoo's safeguards.

Does anyone know of a forum or other site where I could obtain some useful information about this situation. I think he's more of an egotistical pest than an actual threat, but it makes her uneasy.

 

What I would do is just create a second acct and use that for a while, if not permanently. I believe there is also an option to not let users see your online status on websites (I know you can do that w/ ICQ, but I think Yahoo does similar) which MIGHT help. I would definitely keep telling Yahoo what's going on, though.