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Vic Gundotra, who aggressively led Google into the social world with the creation of Google+, is leaving the company.

A Google spokesperson confirmed the departure and CEO Larry Page also sent out an internal memo to staff about the move.

“Today I’m announcing my departure from Google after almost 8 years,” wrote Gundotra in a post titled, “And Then.” “I’m also forever in debt to the Google+ team. This is a group of people who built social at Google against the skepticism of so many.”

Page praised Gundotra, whose departure is immediate.

“Vic cut his teeth on our mobile apps and developer relations, turning Google’s disparate efforts into something great … And, walking onto the stage at I/O last year, it was amazing to see developers so excited about Google,” Page posted on Google+. “These were vintage Vic projects. Then Vic built Google+ from nothing. There are few people with the courage and ability to start something like that and I am very grateful for all his hard work and passion.”

Page also noted that the search giant would continue to invest in Google+, although he gave no specifics. But, according to sources, he has picked a current Google+ exec — VP of Engineering David Besbris — to replace Gundotra.

A Google spokesperson would not confirm who was taking over Google+, but, notably, it’s not Gundotra’s top lieutenant, Google+ product head Bradley Horowitz. Sources did note that Horowitz — who has been at Google+ from the start — was a top candidate for the job.

Besbris has been at Google since 2008, after nearly a decade at AOL. He doesn’t have a huge public presence online, but — according to Google+ — he apparently likes photographing flowers and watching music cover videos on YouTube, and is a fan of the San Francisco 49ers.

The departure of Gundotra will have wider repercussions on what’s next for Google+ and also marks an interesting moment for leadership at the company.

Gundotra — one of the more vocal of Google execs and willing to take aim at rivals publicly, often in colorful speeches — had a long history at Google, which he joined in 2007 after 15 years at Microsoft. Prior to Google+, he led Google’s mobile and developer relations teams, pushing a range of apps and other mobile initiatives, such as turn-by-turn directions, in the early days of the shift to mobile.

Commandeering Google’s great leap into social was a high-profile post for Gundotra to snag, although it may have been less glamorous than he hoped. Google+ faced an uphill perception battle from its earliest days, with a limited launch in the summer in 2011.

Nonetheless, Gundotra — who led the current project from the beginning, after the company’s other social failures such as Google Buzz — took charge at a time when the search giant seemed to have lost a step to its rival Facebook.

Former CEO Eric Schmidt admitted in an interview at the D conference in 2011 that he missed the boat on the rise of identity on the Internet.

“I clearly knew that I had to do something, and I failed to do it,” he said. “A CEO should take responsibility. I screwed up.”

Key to Gundotra’s often pugnacious approach with Google+ was the wonky idea of “circles,” where people could define who they want to share information with in different contexts, rather than all relationships being equal and two-sided, like Facebook’s notion of friends.

“The subtlety and substance of real-world interactions are lost in the rigidness of our online tools,” Gundotra wrote at the time.

While that idea may not have changed the world, the Google+ product was nicely designed from the start and definitely got prettier over time. Today, it has many very loyal users, even though it never has gotten close to picking off Facebook, which may have never been its true aim.

Still, there have been pluses. Social marketers like to take advantage of the site, for example, in part because it is well-ranked by Google search engines.

But Gundotra’s public relations approach of bundling Google+ usage metrics with more established Google products, and releasing big batches of new features at once, didn’t have quite the impressive effect he might have hoped for.

According to the company, as of October 2013 Google+ has 300 million monthly active users of its social stream on Web and mobile, and 540 million including Google products that are “socially enhanced.”

And besides straight social network usage, there’s the nifty free videochat tool Hangouts and rather fancy photo and video editing tools that are among the more impressive features of the service.

While no Facebook killer, Google+ has most definitely become a powerful sharing and identification tool for users and, most of all, for Google. It, along with the success of Google I/O, also vaulted Gundotra into the powerful inner circle of Page, from which he now departs.

Where he lands next will be interesting to watch. Interestingly, a post on the anonymous app Secret last week noted that Gundotra was interviewing elsewhere, but sources said he does not have an immediate plan for a job, although boards and other endeavors are more likely.

On his Google+ page, Gundotra’s introduction notes: “Fell in love with the power of software at age 11, and am still in love.” But in love with what now?

Presumably, we’ll see soon enough.

(You can see Kara Swisher’s ethics disclosure about Google here.)