Moderation can also get tricky. Pure spam is simple but you will run into comments where the commenter somehow works in their (product || experience). So long as they provided some commentary it is not pure spam. So the situation becomes a bit touchy.

This is a problem we ran into at PhpPhotoUploadr. In our case we have a very talented team so we hacked together a solution.

PS: We're always hiring 忍者!