I'm going to keep this brief, since said stalker is aware of my account here and I don't want to give him any more attention than I have to.

Someone who was a general troll to all the female members on a forum I'm a member of has recently decided to focus exclusively on me, even though I have never spoken with him and will keep it that way. I can handle the barrage of porn, sex talk and requests for nude photos, but the cyber stalking is bothersome. This person has somehow been able to find out every single forum I've ever been a member of and my username on them (and they are all different usernames, so he is not tracking me that way). Even forums I've only made one post on or haven't been active on in years. There haven't been any threats against me, only threats to hack into and delete my various accounts, which could be just empty threats, but it is a bit unnerving to keep having this person dig up new info on me that I had forgotten existed.

Can any tech-savvy people tell me how said person might be doing this and if there is anything I can do to protect myself? Or does anyone have any resources they can point me toward? So far all the info online that I've found has been of a general nature and not all that helpful.

Just wondering if anyone has faced a similar situation and what they did about it.