You're kidding right? Someone who knows what to do can track what sites you visit, then hack into those website and editing the javascript. Then, they embed a keylogger into the code, so whenever you enter the site, it will infect your computer. Either that, or they can DDoS you until the sun burns out. Or, call the cops and they will call your ISP for your address. If you really don't think IP can be used for anything dangerous, go on a government site and say you're a terrorist that have placed explosives all over NYC and see how fast the feds show up at your door. You really have no brains do you?