Google is adding more sidebar options to Gmail. Now you can add gadgets on the side that show your appointments from Google Calendar and your last five documents in Google Docs. In the calendar gadget, you can see any calendar you subscribe to and add events directly from Gmail. The Docs gadget gives you a few different view options (only spreadsheets, only presentations, or only documents previously opened by you).
Gmail Labs is also releasing another experimental option that lets you cut and paste the URL of any Google gadget and turns it into a sidebar item. So if you don’t like iGoogle’s new wider look, you can squeeze those gadgets into the sidebar of Gmail.
I personally would prefer to have them in Gmail (because I am constantly in that app), but with the option of expanding them into more screen real estate when necessary.
These gadgets are new entry points into Google’s other apps. I’d expect to see more cross-fertilization like this in the future as Google finds new ways to tie its apps together in deeper and more intuitive ways.