Any guesses as to who is the most popular person on Google+, the company’s new social networking service? Ashton Kutcher, perhaps? Or Lady Gaga?
Actually, that title is currently held by Mark Zuckerberg, the founder and chief executive of Facebook — the very service that Google+ was meant to challenge.
As of Tuesday evening, Mr. Zuckerberg had nearly 35,000 people following his updates on the service, more than anyone else in a broad survey of Google+ profiles by Social Statistics, an outside service.
His fan base exceeds that of Larry Page, one of the founders of Google and its recently appointed chief executive, who had only 24,000 people following him.
Google+ is less than a week old and is still not yet widely available to the public.
But access to the service, which lets people share photos, links, status updates and video chats with groups of friends, is already in high demand among early adopters who are eager to play with its features.
That includes Mr. Zuckerberg, who apparently signed up to keep tabs on his new adversary. Neither Facebook nor Google confirmed whether Mr. Zuckerberg’s profile was real.
But his account is linked with those of several Facebook executives who are also on Google+, including Bret Taylor, the chief technology officer, and Sam Lessin, a product manager, suggesting that it is authentic.
Mr. Zuckerberg has yet to post anything that can be seen by the wider public. His own description on his profile page says simply, “I make things.”
“It makes sense that he wants to check it out,” said Boris Veldhuijzen van Zanten, who is one of the founders of the technology blog The Next Web and built the Social Statistics service on a whim. “Everyone wants to keep an eye on the competition.”
Mr. Zuckerberg’s visit to his rival’s turf may be an indicator that the social networking wars are reaching a new pitch.
Plenty of major companies, including Google, Apple and Microsoft , are eager to gain access to the potentially lucrative trove of social data and other information that people share on these services.
Facebook has long reaped the benefits of having access to such data, which helps it aim its advertisements more precisely.
“The battle for the future of the Web lies in the social experience,” said Ray Valdes, an analyst at Gartner Research.
Facebook also has the world’s biggest map of the connections between people.
It is not possible to transfer data about one’s Facebook connections into Google+, so most users will have to rebuild that list on the new service.
On Tuesday, Facebook blocked an add-on for Google’s Chrome browser that was created by an outside programmer and gave people a way to import their Facebook contacts into services like Google+. Facebook said the add-on violated the company’s terms of service.
Google is hoping to take its new social network to the iPhone and iPad through applications it has submitted to Apple. In the past, Apple has let apps created by Google linger in limbo, without approving or rejecting them.
So far, Google’s new social service has generated positive comments from those with early access, in a turnabout from Google’s earlier attempts to woo the masses with social services like Wave and Buzz, which were met with lackluster responses and concerns over privacy.
Stephen Shankland, a writer for the technology news service CNet, said that Circles, a feature that lets people sort their friends into groups for more private sharing, was “the biggest improvement, far and away, over Facebook.”
Adam Pash, a blogger at Lifehacker, described the service’s Hangout feature, which lets people video chat with as many as 10 friends simultaneously, as “the best free video chat we’ve seen.”
Even Tom Anderson, a co-founder of MySpace who was famous for being every MySpace user’s first “friend,” weighed in on his Google+ page, saying the service “does seem like it could take a bite out of Twitter.”
But will Google+ end up being a mainstream hit? Jeremiah Owyang, an industry analyst with the Altimeter Group, said it was not clear that the successes of Google+ would extend beyond its early test phase, during which the limited invitations are largely being shared among technology industry people, bloggers and journalists.
(As it did with Gmail, Google gave early users the ability to invite a limited number of other users. It is not clear who invited Mr. Zuckerberg.)
Facebook says it is not worried about the competition.
“We’re in the early days of making the Web more social, and there are opportunities for innovation everywhere,” said Jonny Thaw, a spokesman for the company.