There has been a lot of buzz about EBay's San Dimas prototype. Project San Dimas is a hybrid desktop-web app based on Adobe Apollo technology.
There has been a lot of coverage recently from the Web 2.0 Conference: TechCrunch, two of the developers blogs, Rob Abbott and Alan Lewis, and of course the video from the Adobe Conference. (Side Note, Alan has a great presentation, The Future of the Desktop that he gave at Web 2.0 with some great slides on San Dimas.)
The Adobe video highlights some of the features, including the wicked feature that allows you to interact (post items, bid, etc...) with EBay even if your network is disconnected. Ebay will automatically sync up when the connection is restored.
As a side note, there is some interesting shake-up going on with San Dimas project, one of the lead UI designers on the project, Alan Lewis, is leaving the company to join Ribbit. He writes, "Despite our success and raves from the San Dimas team, all design work on our side ended abruptly at the end of Q1."
I have not experienced San Dimas first hand, but I look forward to playing with what Apollo has to offer. It is interesting to note that the screenshots I have seen of San Dimas look somewhat similar to Ebay Express, at least with the controls for query refinement on the top of the page (what Google just abandoned for Product Search).
I will save a in-depth discussion of faceted search and EBay express for another day.