Why is Twitter so successful?

What has made it highly popular and VIP QUALITY ? I dont think its a fad seeing as Obama, CNN and highly reputable people are using it.

The fact that popular/famous people can post things in very short point form and people can read it and be updated on it.

For example: The Old Spice Guy (Isaiah Mustafa) used Twitter to talk to his fans, and he would make them video responses.

Obama can twitter what he is doing at any given time, so people can know what he's doing.

It's a very simple concept: Keeping connected with other people. Now you don't have the phone someone and be like "Hey, where are you?" They can just post on Twitter ("At the mall today. Call me if you want to hang out.") or something of the like.

It's very useful in many ways.