The main thing Google is going for that Facebook doesn't have is an easy way to connect with distinct social circles, as opposed to sharing everything with everyone on one's friends list, he said. Facebook has a friend-segmentation feature, but it's not easy to configure, he said. "Facebook could fix this and likely will. But another round of interface confusion at Facebook isn't going to solve the problem. Google has the advantage of a clean slate," Bernoff said.

Ultimately, the key issue may not come down so much to pure privacy features but to whether Google+ lets users share online in a more natural, intuitive manner, like they do in real life, than is possible with Facebook today, F-Secure's Sullivan said. Whether it succeeds and beats Facebook in that respect remains to be seen, he said.

"Whether or not people will want Google+ once it's ready ... is another story. I, for one, am not yet convinced that it is a more 'natural' way to share," Sullivan said, echoing the opinion of other industry observers who say mainstream users may find Google+'s content-sharing mechanism too complicated to fully grasp.

For now, Google is proceeding in the right way as it fine-tunes Google+, a project of tremendous importance and significance for a company that has struggled with social media and expects to make up for lost ground with Google+, experts said.