Ishmael Ghalimi wrote a series of posts covering his efforts to create "retrain" himself to use hosted productivity applications. (Full disclosure, SAP is an investor in Ishmael's company, Intalio).
I have been fooling around with Basecamp, Writely, various wikis, and many more and find myself having a hard time keeping it up. Aside from the fact that many of these apps are doing the same things or at least strongly overlapping, it's not entirely clear how I am going to realize the goal of having these things meshed together to be a single coherent desktop application.
I wrote about Microsoft's Office Live beta launch yesterday, and Phil Wainewright weighed in with a different view than mine. Phil's point about GMail is probably a spot on one, they are bringing applications to you by layering onto GMail rather than making you go to them, ironically GMail is much more like Office than Office Live is in that sense.
Lastly, Ning relaunched and it appears that they have been busy pulling together a shopping cart full of applets that you can plug together for your own applications. The question remains about how easy it is to actually do this while at the same time delivering rich functional apps, but there is one way to find out... try it, which I will do and write something about it.