smtd

It stands for "Suck my thick dick", this term is commonly used when a person bother you.

Kane: DUDE! I just bought Barbie Dreamhouse Party on steam, you wanna play multiplayer?

Artzy: smtd kane don't bother me with your bullshit

Thread Bomber

Someone that spams the shit out of forum threads with posts

Timid: This guy Kelly is continuously posting on my thread!!

Artzy: I'm telling you he's a fucking thread bomber.