Google module is a module provides one of Widget-like personalized homepage or blog tool, this make user's iGoogle can change dynamically according to your idea from all world wide Google Module designer;
ALl Google module will announce to unoffical wite http://www.googlemodules.com/ , you can search all Google module implementation approach, its XML code is a basic impletation code present in this web site;
For example, Medium Scenic Photo Viewer shows above by object HTML tag through its XML content, in real situation, it is a Google module annonce in http://gmodules.com , so it can also easily show in your blog and web page by iframe and src of http://www.googlemodules.com/ is below.
Picture Shows By Google module through iframe
Music Player By Google module through iframe