I like the idea of new desktop apps. The problem is they don't link to each other. voodoopad comes closest because you can link to other wiki pages using a standard wiki RPC mechanism. But you cant link a voodoopad page to another user's voodoopad page.
I also looked at delicious library which sounded very cool. Create a catalog of all the books and stuff you own and share it with others. This is just a killer app waiting to happen. While delicious library looks good, it ain't it. I thought for sure my friends could download their own delicioius library client and browser my database. Nope. Its single user only. What a letdown. Not only that, but the entire app appears to be a sales tool for amazon. Its genious in a way, it leverages amazon's massive product database to generate info that is locally useful to me. But from the looks of it the library is only good for cataloging categories of things that amazon has large categories of.
So bring on the distributed apps. One thing thats cool is that voodoopad, etc appear to be ahead of the curve, even ahead of opensource development (i got the feeling tomboy was a proof-of-concept that has since been shelved). They can charge a fee for a good app and people will pay it because there is nothing like it in the open source world (for a while). The same appears to be true of ruby IDEs. The open source world hasn't developed anything outstanding yet.