Microsoft’s new web application Popfly is now beta. Along the same lines as Yahoo Pipes, and Google Mashups, Popfly allows users to easily build pages by mashing together the content of popular sites such as Flickr, Twitter, Digg, and Virtual Earth. All of this is done through a drag and drop interface but what’s interesting is that it is powered by the Silverlight browser plugin. For those unaware, Silverlight is much like Flash. Check out Flickr Mappings to see Popfly in action.