What does the # mean and is it called hash tag?

[daddeo01905]

answers
Seeing this more and more but never learned what is meant or where it came from.

[Jay T]

The hash tag allows you to tag items in both twitter and instagram, which are newer forms of social media. The symbol makes it easier to find people and topics listed under the "tag". For example #sleeping or #winning.

[Matt Hoffman]

comes from twitter, if you were mad about the replacement refs screwing up the game for the packers you could say something like "Damn replacement refs #nfl #packers"
When people search for #nfl or #packers they can see all tweets that used that hashtag, twitter also keeps track and shows you whats trending, the top hashtags
People use them on facebook all the time, which is pointles

[HAL]

In less trendy contexts, # stands for the word, 'number' or the weight unit, 'pound(s)'. On the phone keypad, it's usually called the 'pound sign'.

"Please use a #2 pencil."

"Annie from Brighton once ordered a steak weighing 9 3/4#."