Well, THAT just sent me searching, and I learned a new piece of slang.
From urban dictionary, re 205:
1.) 205 (Two -oh-five) is a term used when a subject is introduced as if new, yet everyone else has heard of it previously.
2.) Used like a shorthand response when a nOob posts an image or notable news to a message board or email list in which all participants have beaten the subject like a dead mulie.