Last Friday Microsoft announced a new product family under the heading Popfly.  Popfly leverages the recently announced Silverlight technology.  Silverlight allows you to create interactive media style applications for the web.  Popfly is focused on taking items such as Silverlight applications or other existing web contact and pulling these individual resources together to form larger applications.

The basic idea is to create "Mashups", what's a Mashup, well in short in terms of Web applications, a mashup is a web page which combines content from multiple sources.  The terms been around long enough for publishers like WROX to actually create books on the practice (such as this one on using Flickr: Mashups for Flickr).  Currently however, to create these technologies you are essentially working from scratch.

Popfly is a set of extensions for Visual Studio as well as a Live Spaces area to allow you to really start creating Mashups in a more drag and drop fashion.  The basics of the tool are available at http://www.popfly.com and for additional resources I suggest going to this blog entry from Adam Nathan and checking out the demonstration video he links to: http://blogs.msdn.com/adam_nathan/archive/2007/05/18/yes-i-m-on-the-microsoft-popfly-team.aspx

It's going to allow many more people to create sites with a great deal more interactivity.  It's still in Alpha and you have to apply to participate on the Popfly site but it definitely looks cool.