The term used for any bot that has hacked someones personal IM account such as Yahoo Messenger, AIM, MSN, Skype, and even Facebook to advertise an annoying product to you which most likely has no relevance to you whatsoever. Often they try to get you to take an IQ test. They begin conversations as you normally would with the person the IM is coming from, and eventually send you a link to the spamming website. They can often pick up on words such as "bot" and "spam" and try to prove you wrong, but only to an extent. They can even respond to threats to call the police. The only way to get rid of these is to change a password, which will only work for so long.
Loo(Bot):I just took an IQ test here... pretty cool :P
Me: um... okay?
Loo(Bot):I scored 113, I thought I was smarter than that! lol
Me: Thats... nice? (you and every other bot)
Loo(Bot): you should see if you can do better than me... http**************.com if you can ill give you twenty dollars lol
Me: well bye then. F****** hackbot.