The first addition is for maps users who have enabled Google Latitude on their profile. If you choose to, you'll now be able to view stats and graphs of your location history, including estimates that break down how you allocate your time at work, home, or elsewhere.
Maps' second feature expands the pre-existing Latitude check-in option to let followers and friends know you're at home when you're not out. You can tap Home to associate your location with your personal fortress of solitude.
Finally, Google Maps 5.3 tweaks the way you rate establishments in Hotpot, its reviews engine. Now you can add not just comments, but traits that define a business, like a swanky bathroom, great music, or comfortable chairs.