I mostly use 3 mobile websites that I access using my LG Chatter box cellphone
The mobile website is a simple version on the online website and offers status updates, friend requests, notifications and messages.
You can view photos, do mobile photo uploads and interact with other users.
This is a great site when I am waiting for my daughter at school or when I am sitting waiting for someone and I am not close to a PC.
Mobile URL Address: http://m.facebook.com
I can set-up my cellphone with an email account so that it can automatically gather mails as they arrive or every x amount of minutes but since I do not need access that often, the mobile option is cheaper to access when I actually need to send or receive a mail.
Simple interface that does not use more than 450kb whenever I do make use of it. It would be great if all cellphone contracts worked like the BlackBerry packages.
Mobile URL Address: http://m.gmail.com
By default when I open my phones browser I am offered the Google Search option.
From time to time I might use this to search and view information.
Aside from these 3 mobile websites I do not really use any other mobile websites but prefer to use applications developed for certain functions. As my phone does not support the GTalk App, I would replace that with Mxit that connects to my GTalk contacts.