We recently covered the upcoming "Astra" version of our favorite multinetwork IM client, Trillian. In that story, we also reported that there's a Web-based version of Trillian in the works that will compete with Meebo (related posts).
We just heard that the Trillian Astra Web client is going to be much more than a Web page. As Trillian head developer Kevin Kurtz shows in a demo video, Cerulean Studios is prepping a sort-of-Web-based version of Trillian that requires neither a Windows installation nor a running Web browser. Based on Flash (but not the upcoming Apollo platform), the new floating Trillian app is kicked off by a Web log-in, but after that it runs independently of the browser. Read more in Kurtz' blog post.
Really more app than Web service, the new client has access to the PC's system tray, the file system, and more. If it works as advertised, it looks like it will do a nice job of giving users the best combination of real application features without the hassle of actually having to install an app itself.
In other words: Pretty freakin' cool. No word yet on when it will open up to the public.