Similar to an inside joke, inside baseball refers to a reference that is not well-understood by the layman. An average person without deep knowledge of a topic would not be able to understand a reference that is inside baseball.
"I got kicked out of the raid for not having B4B"
"That is too inside baseball, I don't get it.
An AIM bot used like a three way call; The Salmon (using a screen name with Salmon in it) IMs you when you update a website like LiveJournal (assuming you have provided a screen name on your profile) and when you respond, you are connected with another person being Salmoned at random. This usually results in confusion for both parties but in lulz for the operator salmoning, who gets to read the entire conversation until they begin using their own screen names to talk.
Salmoning is probably fun but the operators never say who they are.