Used to be the sign for a number, but thanks to goddamn twitter its called a hashtag. possibly the most annoying key out there that kids use these days before the dumbest sayings and words. And don't think I'm an old party pooper because I'm 15 and saying this.

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life

The official symbol of attention seekers on the internet

The most annoying piece of shit in the world. It is commonly used by attention seeking whores. Some uses for it USED to be:
Number sign
Sharp sign (in music)
Tic tac toe grid

But now thanks to twitter its a "HASHTAG". Used by annoying people.

Some people who use it:

99% of my school
Whores
Obnoxious hypocrites
Anybody I hate

Used as a tagging marker in Twitter for creating lists and groups.

The short way for saying hashtag, which is the better way of saying pound sign, which is the short word for the ridiculously long word octothorpe.

used as tagging marking on twitter and also means "number".