I've been testing this system for a few weeks now and it is proving invaluable. So far I have used it to share my screen as part of a training session (I was on a conference call with a group and then directed them to my screen), used it to show someone in IT what was happening when I tried to use their new system and used it in a coaching session where I could dircet someone how to log on to a new system we're using.
I like it because the other party has no software to install and is very quick to set up. I reckon it takes me 15 seconds to set up a sharing session and it seems to take about 30 seconds for the other user to then get access to my screen. What I like is the fact I can choose to share at a moment's notice and it works.
You just click on the G button on your taskbar and you are automatically given the session ID which you tell to the other person, along with your bespoke web address for the session. They go there, put in the session ID and they get to see your screen.
I have two screens and the Glance system chooses to share the main one. This was a key test for me because most other screen sharing systems get confused and I have to go through (the nightmare) of resetting my screen settings (and then remembering how to get the second screen up and running again...).
www.glance.net if you want more info and to download a trial.