Enough people have mentioned Trillian to me lately that I should probably consider its importance. There may be others, but Trillian is the only instant messenger I'm aware of that works with all other messengers-- Yahoo, AIM, MSN, ICQ and soon Jabber's Exodus, I believe. The suggestion, along the lines of what Michael Bernstein has argued, is that GlobeAlive use an interoperable chat proxy on the user side (something like Trillian) and let the experts/participants use their own favorite instant messenger, whatever it may be. This would dramatically increase both sign-ups, and more important, quantity of participants online at any given time, as there would be no GlobeAlive Desktop to download or keep logged on.
We're already working on making GlobeAlive compliant with a Jabber client to eliminate GA Desktop, but this will still require experts/participants to download a new messenger. If indeed there's a way to do it, it's certainly preferable to let the experts/participants use their own favorite messenger (which they already use regularly) to interact with their visitors at GlobeAlive. But Trillian, unlike Jabber, is not open-source, and without a formal partnership with them, we could not use their code on the user side.
I wonder if there is a Jabber client that allows users to chat with any of the other major IMs? In other words, a Jabber client that does what Trillian does? Conceivably one could be created from hacking a current Jabber client, but our programmer mentioned that creating a Trillian-type chat from scratch is an enormous undertaking and not one he's prepared to even consider at this point, which is understandable.