So I read about Microsoft's new website and mashup building tool, Popfly, on several different sites this past week, so I thought I'd give it a try myself. I wasn't that impressed. The service looks very powerful and like it has a lot of promise, but it's definitely not there yet. It continually crashed my browser (both Internet Explorer and Firefox) and even made my streaming music start skipping, that's how much of a drag it was putting on the system.
Granted, I'm using an older laptop (1GHz processor, 512 RAM), but still, we're talking about a web based application, here.
Anyway, Popfly uses Microsoft's new Silverlight plugin, and allows for the creation of mashups using "blocks" from tons of different services, from Flickr to Facebook, XBox Live to RSS feeds. You can combine these various blocks, link them together, add special display blocks, etc. to create some really cool customized mashups which you can then save and publish to your own Popfly page.
I fully intend to try it on a faster computer as soon as I get a chance.
I wholeheartedly recommend following the tutorial on the right side of the page when you create your first mashup. It's a slightly confusing process, and the tutorial helps a lot. Give it a try, let me know what you create! :-)