Forum owner taking advantage of your IP address to see your online activities?

Question

if a forum owner knows your IP address, is there a chance that he might search your IP address and find what other forums on the WWW what you've been posting with your IP address?

Answer 1

Not unless he has admin access to those other forums. Most forums do not disclose IP addresses of other users publicly.

Depending on your ISP you may not even have a static address anyways, so if another user has your IP address there is nothing to worry about, tons of other people have used that address before too and yours will change again regardless.