OpenSocial is a set of APIs promoted by google for developers to create applications that makes use of the information found in social networking sites. Almost all major social networking websites now support the initiative.

This API will allow developers to create applications that run across all the social networking platforms that support OpenSocial. Code once and run everywhere. The apps are written in HTML and JavaScript.

Here are some of the applications that are already written.

ILike – Shows a playlist of all the songs that you like on your profile page

ComicGadget – Select a comic to be displayed on your profile

There are many more. If you have any ideas, add as a comment to this post. Ill get it done for you.