The Need For Twitter????

The newest craze in technology is Twitter. What is Twitter?? I don't think people who use it even know what it is. I do know that famous people; a.k.a. actors, athletes, superstars, use it to "inform" their fans of what they are doing. But why do people even want to know when and actor or actress is sitting in their living room eating ice cream? I could understand if they were informing people about an upcoming appearance in public or about a concert that is coming up; but I do not see the need for anything else. Also myspace and facebook already have similar devices on their networking systems, so there is really no need for twitter. I have seen recently on TV where you can order a pizza or get a "tweet" from Domino's about deals. However, if you are already on the internet, it is much simpler to go to their website. I guess what I'm trying to get around to saying is that I do not understand why someone would feel the need to inform everyone and their brother of what they are doing at every minute of every day. I do not think I have ever sat down in front of the TV recently without viewing something that has to do with Twitter. I have even heard about Twitter on the radio. I hope someone could answer this for me.