What does hash tag mean......?

[?]

When you write it on internet? I hear a lot of people say it as well

[Nicolas]

this: #

[Winny]

http://readwrite.com/2009/03/20/what_doe..._tells_you

It all started on twitter, but everyone uses it now, Read that link tells you everything.

[JellyFish]

This # is called a Hash Tag and it's basic purpose is to stop people from Copying, defacing or altering other users Names or links to other internet services.

[ihsan ehmad]

its Like a Topic..You may see it at Google+ and Twitter... Like #Obama

[o-maria]

This # is called a Hash Tag used to make topic obvious when clicked all relevant to that topic will appear (everything with that word in it) xxxxxxxxx