How MVC in twitter working?

[eluser]Dinesh Viswanath[/eluser]
Hello,

I’m quite new to CI. I would like to know how MVC concept in twitter working? May be my question seems to be silly but Pls help me out.

Twitter’s URL (which uses MVC framework) looks like www.twitter.com/dineshviswanath
Dineshviswanath is the user name. It implies me that new Controller has been started when user registering in twitter.
1. My question is that can we create controller at runtime dynamically in Codeigniter? If so how..?
Thanks in Advance