If you use Twitter on your Internet Explorer 6 or 7 browser, then you will see mobile.twitter.com instead of twitter.com when you log in.
Not all twitter.com features are compatible with IE6 or 7, so we have started to direct all IE6 and 7 users to mobile.twitter.com to provide the most stable experience within the browser.
If you would like to use the standard version of Twitter from your browser, we recommend an upgrade.