When did we start calling the "pound-sign" hashtag , and why ?

When? Seems like the late 19th century the "#" was substituted for the British pound sign. At that time there were already international variations in what the # was called, the pound sign in USA & Canada, vs has in Great Britain. Interesting history of different uses.

http://languagelog.ldc.upenn.edu/nll/?p=2461

Since the US and Canadian word was pound sign, but British called it hash, it makes sense to choose the only one of the two for worldwide use. The other meaning of "pound" is a financial which of course is not the same thing.

http://www.oxforddictionaries.com/us/words/what-is...

I know right?! It took me FOREVER to figure that out. I always thought a hastag was this "/". Whoever would of thought to cal this "#" a hashtag?!

From the article below, it seems the hashtag was just some techs technique to market the idea of using the "#" sign to group several similar topics. In short, hashtag is slang for pound sign.

Pound Cake Slang

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£ sign, # hashtag

2 different things

so to answer you when? never

When Obama said to !

1970's...

http://en.wikipedia.org/wiki/Number_sign

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