commonly web host encounters problems?

Can you be a bit more specific?

Clients using too much disk space. CPU and memory can be quite a common problem.
 
Fraudulent orders.... Namely letting the bad guys in who try to spam the world or setup http torrents.

I had this happen once and it caused me a world of pain. You get blacklisted, which may cause you fines from your ISP, your get on spam block lists, etc. I know setup things different to handle such things and haven't had a problem since.
 
Spam seems the be the biggest issue. If you can find a good mail provider to offload clients too for a minimal cost, i would suggest it
 
Top