how do you use twitter?

[Fester Frump]

@(someones username) would insure that message appeared on that persons feed, even if they don't follow you. Everyone who follows you also sees messages you send with the @(someones username) in them. Say you wanted to send a message to a specific celebrity, you would tweet with @(celebrity twitter handle) in the message.

#(some word) is a searchable item, a.k.a. a key word, usually specific to a subject that a lot of people might be tweeting about. You search on the key word and you will find all tweets with that key word regardless of who sent them. Mostly useful when some major event is occurring in real time.