1. Make fun of their lame threads.
2. Point out the fact that they post 10+ times a day, usualy no more than a sentence, commenting on a comment that was originally left for an actual idea.
3. Also point out the fact that none of their posts are realavent to anything.
4. Tell them that their signature sucks.
5. TYPE IN ALL CAPS!!! AND USE ALL THE SMILEYS THAT UM CAN OFFER!!!!11
6. Remind them that they are on the internet. Sometimes forum posters forget that they are on a computer that connects to the information superhighway. Make sure you let them know before their head gets too big.
7. Tell Will that Distorted Mind Sucks.
And if all else fails, you can always call them a homosexual in any way possible, because that is the Mother of all insults on the Internet.