Explain the @ or # in front of nouns on Twitter (ie, @Twitter)?

[dayglo dog]

I totally do not understand these symbols or what they mean, and whether @ means one thing and # means something else. Thanks!

[Who is on first!]

@ is the symbol for at, so my guess is that they wanted it to be displayed as if it was the second half of an email address minus the .com, .net, .org etc.

# is the symbol for number, but i don't know what twitter uses it for being that i don't have a twitter account.

both are just shots in the wind for me.

[SPM]

@ is used when you are replying to or mentioning someone else in twitter (if you want to see if someone has mentioned you in their tweets, click on @mentions in your home page) . While # is used to make the keyword following it as a topic of discussion. For example #Egypt is a topic of discussion. If you search Egypt in twitter, all the tweets that have used # Egypt will be in the result...

[Stephen]

the @ means you a mentioning someone else on twitter

[Umang]

The @ sign is to mention someone on twitter, or to reply to someone's tweet. The # sign is for the trend. It's about the topic you're posting on. For eg., @umanghome is using @yahoo #YahooAnswers