How dangerous is it to allow E-mail and IM on this site?

Its not really dangerous to allow e-mail to come through--however it can get annoying if you are spammed. If you scan all of the messages before you open them you should be safe. However, when you are on AIM your ports are open. When this happens, another person simply has to dial into that port, and when this happens, can place viruses on your pc without any knowledge from you. If I were you, I would allow E-mail not IM