Depends, they can ping you to death or they can hax right in and steal all your food coupons. Make sure your firewall is set and block all requests you don't know. It's easy to get someones IP by the way.
My IP address has been posted on online forum so I was just wondering what's the worst thing that can happend to me.
So you upset someone online and that person was childish and posted your IP? Silliness... It's likely that if you turn off your cable/DSL modem for a while (and then turn it back on) that you will be assigned a new IP. Sometimes ISPs are stubborn, though, and won't assign a new IP unless you're disconnected for a while. You probably don't need to worry about it as long as you're behind a router...
