Google has rolled out extensive changes to its Buzz product, following privacy complaints from the Web. Bloggers were up in arms that the service displayed your contacts publicly - which are by default your most-emailed people on Gmail.

Now, when people first sign up, the service asks you to confirm what details will be shared with the public. At minimum, that's your first and last names, and there's a checkbox to show the list of people that you're following and who are following you. You can view, edit, and hide the list entirely.

Google has also made it easier to block people who are following you, if you so desire. Previously, you could only block people who'd created a public profile. Now you can block anyone. Lastly, Google's offering more information on which people following you will appear on your list of followers.

Google says that Buzz has been proving popular, despite some web scepticism. The search giant claims that "tens of millions" of people have accessed buzz, creating more than 9 million posts and comments. There are 200 posts per minute from mobile phones around the world.