What exactly is Twitter?

[JackieO]

I know it sounds stupid, but I don't really get this whole twitter thing. Like can everyone read your text messages if they subscribe to your account or something? Do you have to invite people, or can Joe Blow come and see your messages? Do people like read celebrity twitters? It all seems strange to me... Whats the big whoop anyhow? Just wondering. I'm not trying to offend. I'm the one who doesn't understand things anyway, so...
Sorry. I thought this was society and culture. And as a society, people are using twitter. I don't know how it got into languages anyway... But humor me.