Let's see who couldn't upgrade if they couldn't access facebook anymore -
since now facebook has become a part of the corporate world presence.
Also, how many users would crap their pants if they couldn't get on
facebook (youtube, twitter etc). I bet you 99.9999999% of all users would
upgrade and this whole conversation would be a mute point and we wouldn't
have to stand here with our thumbs up our butts coming up with excuses for
why we should support IE6 or for that matter any browser that is not web
compliant.
Most of those users would be trying to access them at work