Why do they call the pound sign a HashTag now?

[Kevin]

[airdogspace2]

Hash tag is lingo for Twitter. Its still called the pound sign, but when you use it on twitter and use a pound sign plus some "tag" then it becomes a hashtag.

[Ryudeshi]

That symbol is also called a Hash, although not very common in the United States. Hashtag is just a new form of it where you use the Hash/Pound symbol and add a "tag" to it, usually a word or group of words. Website and apps like Twitter, Instagram and Facebook use this to link other posts using the same Hashtag.

[Beauty Tips 101]

The pound sign is also known as a "hashmark". Twitter started a way of tagging random words by adding the hashmark in front of it and joined the two words making it a "hashtag". Now it is used on instagram aswell. Just another way of connected random people.

[robert m]

It never was pound outside the US. It's a hash, hence when used as a tag it becomes a hash tag...