New acronym for the internet meaning "Shut Up and Move On." Too often, arguments on internet forums turn into constant shoutfests with no beginning and no end. These arguments will never solve anything. Knowing this, the only way to end the argument is to just give it up entirely and move on to more pressing matters.
So, just tell the person on the other side of the argument to SUMO: Shut Up and Move On.
Just, please don't use it as an insult.
Let's just get this over with so we can get back to being reasonable people. Arguing constantly won't help anything anymore. SUMO.