A lot can be done with an IP address if you know your hacking. I remember one from my online gaming days a couple of years ago where someone scammed another player but it turned out the guy who was scammed was a real computer geek.
He traced the guys IP and hacked his computer, got all his personal details, posted his yearbook pictures (USA obviously), enlisted him on about 300 free porn site trials, published his name and address, sent his parents emails on what he had done, did some more but I can't remember what else but I think that scammer really regretted scamming someone who knows his stuff around hacking propoerly.
If the screwing around was done from an office then I wonder what the guys boss will think of him using office equipment and presumably work time to attack internet sites?