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.