Subdomain instead of long URLs for each user profile page.

How much work would it take to turn long urls into subdomains? ie shortening it a little?

For an example, instead of http://www.profilactic.com/mashup/smo...
We get: smorty71.profilactic.com
As for menus, there would also be when selecting from menus:
smorty71.profilactic.com/profile
smorty71.profilactic.com/clippings
smorty71.profilactic.com/friends
and smorty71.profilactic.com/friends/mashup

It would save especially mobile users(when you have to hit 2 strokes to get the slash key) a little time typing in the url.

Or at least having a subdomain that redirects to the longer default URL.