The APIs stuff is just making life easier.
Gadgets are like small applications we play with at different platforms.
Google already have gadgets platform available at iGoogle. Now google introduced Gadget Ads for Adwords. Now you can have more interactive ad campaigns with gadget ads.
For opensocial gadget developers there is nothing to do. New developers needs little effort for.
First thing we need to sort out is the Gadget API.
Currently there are two versions of Gadget API. One is the Legacy and other is a “renamespaced” to gadgets.* an advanced one.
Gadget Ads are currently use the Lagacy Version of Gadget API. The documentation in previous link simplifies all about Gadgets.
Finally go through Gadgets Ads and move ahead to start yours.
Gadget Ads need a little alteration to Gadgets. We can use Gadget Ad Editor for writing, testing, validating and publishing Gadget Ads.