Google Buzz on a phone is the opposite: You don't need Gmail. And you can see the tweets of people whether you're following them or not. In the "Nearby" mode, you're automatically "following" whoever happens to be or has been near wherever it is you are. And they're following you. When you leave the area, you stop "following" them and start "following" the people near your new location.

The power of Google Buzz on a GPS-enabled cell phone is abstract, and it must be experienced to fully understand it. But until you do, let me tell you eight things you can do with Google Buzz on a compatible iPhone or Android device that can change your life:

Last year, one of the big stories on Twitter was food trucks selling cupcakes or Korean barbecue via tweets. Bakeries would tweet when fresh cookies were coming out of the oven. Small businesses of all kinds were first promoting their Twitter feeds, then using those feeds to promote time-sensitive information to customers.

Google Buzz can do the same thing, but with two very big differences. First, you don't need to know about the business in advance, and second you don't need to follow anyone. When you use Buzz to check what's going on in your location, you get the posts about it all -- cupcakes, Korean, cookies, you name it -- without following any of them and without any advanced knowledge or action.