If you see a user that is obviously a spambot, be certain to alert a moderator so it can be shut down before it floods the boards with advertisements.
What is a spam bot? It's usually a badly named user with a name like Geffexejepe, though not always, it can often also be two full names, and it usually has an advertisement website in its profile to something not allowed by the forums.
Often they will post an advertisement, if you see a post about the 'Hair Club for Men' you know it's a spam bot.
Also, of course, there can be people soliciting donations. This is not allowed without moderator approval, and in such cases, I will require a moderator to post that it is approved. So if you see a non-approved request for a donation, report it, don't respond to it. There are some pretty subtle ones out there that sometimes come to Catholic boards, pretending to be seminarians, third world people in need, etc.
Many spambots will try to get you to contact them via email immediately to take the conversation off the boards and avoid moderation. So be careful out there! If something seems odd, ask a friend or moderator about it.
Spambots bother all forums, and cannot be completely gotten rid of, once you delete one, eventually another comes along. Whether you see any of them at all for more than a short time depends on how fast the moderators are at this little 'whack a mole' game.
And if you receive any emails from Nigeria telling you, you inherited a million or won the lottery, don't answer them either!