Since iGoogle is retiring fully in 2013, the Google Gadget editor will be effected. Referred to as the Google Gadget Gallery in Google Sites, this gallery of published gadgets will go away. The functionality of xml gadgets will be constant though, so prepare your websites.
Quoted from Google:
As we announced on the Official Google Blog, on November 1, 2013, we will be retiring iGoogle. To ensure a smooth transition for your users, you may want to update your gadgets and direct users to your site or offer the ability to export user data. You may also consider launching your application on one of our other platforms.
Similarly, we will stop accepting new gadgets after July 31, 2012 - but you will be able to update and maintain existing gadgets, as before.
What to do
Take the initiative to host your gadgets (look for the .xml file) on your own Google Site. You can upload them anywhere on your site and use the "Add Gadget by URL" feature.
I'll let you know if I hear anything important on this topic.
The functionality of the .XML gadgets is solid and won't change, just make sure that your gadgets are hosted elsewhere than the Google Gadget Gallery. I'm not exactly sure is the Gadget Gallery will go away completely, but better safe than sorry. It certainly is a nice tool when your looking for those oddball gadgets like the Frogger game, news from Tahiti, and a non-functioning clock.
How do you feel about this update?