For the second time in less than a week, Google is responding to criticism over its Google Buzz feature, revamping the service's privacy settings again to address user concerns.

Google launched Buzz last week as an enhancement to its Gmail service that makes it a more social experience, layering a social network similar to Facebook atop a user's existing contacts. It also auto-populates that network with frequently-used contacts.

But critics quickly blasted Google's privacy settings for the service, which automatically publicly revealed those contacts with whom a user communicates most frequently.

The company responded on Thursday with a handful of Google Buzz interface improvements, highlighting the checkbox that keeps a user's Buzz followers private to make the option more prominent. Google also made it easier to avoid unwanted followers with others through a new "block" link that circumvented a previous limitation of blocking only followers who had public Google profiles.

Now, Google is responding further to user feedback with a set of additional changes designed to address the outcry over privacy.

For starters, it's now dropping Google Buzz's auto-population of social networking contacts in favor of simply suggesting contacts to begin following.

"After hearing that people thought the checkbox for choosing not to display this information publicly was too hard to find, we made this option more prominent. But that was clearly not enough," Todd Jackson, product manager for Gmail and Google Buzz, said in a blog post on Saturday.

"Instead of an auto-follow model in which Buzz automatically sets you up to follow the people you e-mail and chat with most, we're moving to an auto-suggest model. You won't be set up to follow anyone until you have reviewed the suggestions and clicked "Follow selected people and start using Buzz," he added.

The change only impacts new users joining Google Buzz. Jackson also said in his post that "over the next couple weeks" existing Buzz users will receive a similar screen enabling them to quickly edit the contacts that they're following.

More Google Buzz privacy changes

Google is also rethinking its approach to tying Buzz into two services, its Google Reader RSS reader and link-sharing service, and Picasa Web Albums, Google's photo-sharing service. Previously, Buzz automatically linked users' activity with their publicly shared Google Reader and Picasa activity. But following this weekend's changes, activity on neither service will automatically be shared via Buzz.

Google also said that it's adding a Buzz tab to Gmail Settings, enabling users to hide or disable Buzz entirely. It also plans to add a link to Buzz's settings from its initial startup page, "so you can easily decide from the get go that you don't want to use Buzz at all," Jackson said in his post.

It's not clear yet how much of a favorable impact the latest round of changes will have on Buzz's public perception, nor on its usage. In a blog post last week -- prior to its first set of tweaks -- Jackson said tens of millions of users had "checked Buzz out" and sent more than 9 million posts or comments.

And despite having had to undertake a second public attempt at revamping the service, Jackson said that Google is indeed listening closely to its user base.

"It's been an exciting and challenging week for the Buzz team," he wrote in Saturday's post. "We've been getting feedback via the Gmail help forums and e-mails from friends and family, and we've also been able to do something new: read the buzz about Buzz itself. "

"We quickly realized that we didn't get everything quite right," he said. "We're very sorry for the concern we've caused and have been working hard ever since to improve things based on your feedback. We'll continue to do so."

Christopher Saunders is senior managing editor of, the news service of, the network for technology professionals.