1) Acronym used for the phrase "shut the fuck up" for efficiency reasons.

1.) Save The Freaking Unicorns
2.) Say, Thanks For Understanding
3.) Short Term Follow Up
4.) Special Task Force Union
5.) Stop Talking Find Username
6.) Slippery Teflon From Utah
7.) Stinky Telnet Fell Under
8.) Special Transitory Food Units
9.) Stealing Turkeys From Uncle
10.) Superior Tactical Fragging Unit
11.) Silence That Followed Us
12.) South Texas Farming University
13.) Southern Tenant Farmers Union
14.) Scrawny Two Faced Underling
15.) Samurai Training Finished Unsuccessfully
16.) Show Them Fury Unleashed

Or the most common definition:
17.) Shut The Fuck Up
The common response to the previous 16 definitions.

When someone won’t shut up

"Shut the Fuck Up"
To the extent of being universally known, consistently used online, both on multiplayer games and messege boards.

Practiced in anger or irritation, to get someone to remain quiet.

With or without "Bitch", "Woman" or any demeaning and vulgar slang to show pwnership.

abbreviation for shut the f*ck up.

AKA::

Stop
Tickling
Furry
Unicorns.

An abbreviated form of:

Shut The Fuck Up

Often used in the popular internet comic "Little Gamers" and on internet message board and chat rooms across the nation.