Microsoft has opened the beta program for its new mash-up building system Popfly, unveiling the consumer-orientated tool to the world at last week's Web 2.0 Summit in San Francisco.

Popfly is a hosted application that enables people to assemble mash-ups by dragging and dropping components, rather than writing code. It's built with Microsoft's Silverlight Web browser plug-in.

When Microsoft released the alpha in May, it had pre-built "blocks", or connections, to popular Web sites Flickr and MySpace.

Now it integrates with Facebook and people can create gadgets (also called widgets) that run on Windows Vista or Windows Live.

With Popfly, people assemble mash-ups by connecting blocks. (Credit: Microsoft)

There are a growing number of these do-it-yourself Web authoring tools, including Google Mash-up Editor and Yahoo Pipes.

For business users, IBM has developed QEDWiki and Coghead, and other companies have created hosted application development services.