Microsoft disclosed Popfly today, as the "fun, easy way to build and share mashups, gadgets, Web pages, and applications." We will be showing it off at Maker Faire this weekend. Mary Jo Foley and TechCrunch have some nice coverage of Popfly as well.
Popfly - which is based on Silverlight - consists of two parts:
1) Popfly Creator - a set of online visual tools for building Web pages and mashups.
2) Popfly Space - an online community of creators where you can host, share, rate, comment and remix creations from other Popfly users.
Here's an interesting piece of behind the scenes info - the Web page creator is based on the Office Live code for Site Designer and Page Editor. Not many people know about them yet, but these tools make it easy for non-technical folks to easily create Web pages, style and theme them for their public facing web site. It's exciting to see that technology being used now in the Web 2.0 mashup context in Popfly!