How MVC in twitter working?

[eluser]xwero[/eluser]
The problem with a one segment url that can be anything is that you have to add all the controllers that also can be called using a single segment.

Code:

$route['(shop|blog)(.*)'] = '$1$2'; // example of a few controllers that can have a single segment url
$route['([a-zA-Z0-9_\-]+)'] = 'users/profile/$1';

The username segment is best limited to the constraints of the username input, for example if the username has to be at least 4 characters the regex would be ([a-zA-Z0-9_\-]{4,}). This cuts down the checks for none existing usernames.