Actually, it is
Here's an example of bad things that can happen with your IP. This one guy used to be my best friend (bad things happened that changed that REAL friggin fast) and he pissed me off one day. Beings I knew the root password to his computer and his IP address, what I did was port scan his computer and found the ports that were open (He used Kazaa, and beings that is a HUGE frikkin port to be open, I took advantage), ran about 12 65kb ping attacks dropping his bandwidth down so hard that he couldn't even stay connected to AIM (my download pwns all upload...), then I turned those off when he left his computer thinking that his cable was out. Then I made a telnet session using that port, logged in under the root account and loaded him up with a stealthC boot virus (really OLD virus) with a timed BAT file to launch it.
Now, how dangerous is it that I know everyone's IP address?
In case you were wondering, I cleaned up my mess like...2 days after I did it...drama is bad enough without jail time...of course then he deleted a lot of my site (he had FTP access that I had givin him a long time ago, what a 1337 hax0r he was :rolleyes) so um...I don't think I'll be getting in much trouble for letting the whole world know of my mallicious computer crimes.