Don't give out your email randomly and don't open spam from people you don't know. Beyond that... take your paranoia meds. There are dozens of ways someone with a lot of skills my hack your PC. But don't get too full of yourself. Hacking one single poster because your don't like a post is like punching a single raindrop because the rain is hitting you in the head. No one woud do it because it is a waste of time. You are more likely to get hit by a drunk driver. Relax.