Google+ - Guesses where a user might work based on where their friends work.
/via Artem G.
Chrome - When deleting lots of individual items from your history, Chrome suggest trying Incognito mode (which doesn’t record history) in the future.
Google Flight Search Results - On mobile, Google flight status results include an airplane placed on a line at a point relative to its flight progress. Color communicates whether the flight is on time or not.
/via Erin Olmon
Google Calendar - If you hide several calendars in the list, options menu for the next calendar will default to hide when you expand it.
/via Marina Janeiko
YouTube - When typing in the search box, recently made searches are shown in purple.
/via Davide Dettori
Google Analytics - To select a period of time, you can select a complete month by clicking the month title
Google Images - When searching for some images which are somehow connected with recent events, it shows a little label with its age
Gmail - Typing ? in Gmail (when not in a input field) gives you a cheat sheet of all available key commands.