As recently reported by Go2web20 blog, Gmail has apparently begun to accept the use of iGoogle's degadgets through the experimental "Add any gadget by URL" feature, allowing you to bring additional tools and content into webmail.
In our tests, gadgets created by external developers were more likely to work. For gadgets created by Google, Gmail has even allowed it to be included but for some reason or mismatch does not display your content.
Have a try: After enabling experimental functionality in Gmail Labs, go to the iGoogle gadgets directory and choose a favorite. That done, just copy the end of the Gadget URL. Ex:
Paste the address into the respective field inside Gmail (sometimes you need to add ?http: //? at the beginning of the URL) and view in the sidebar the insertion of the new element. It worked? Leave a comment on this post so other people can use it too.
Thanks to the readersbel towers for the tip!