Three years ago Larry Brilliant joined Google to head up its philanthropic arm: today he announced that he's parting ways with the internet giant.

In an announcement, the 64-year-old said he was leaving Google.org to join a new organisation set up by former eBay president Jeff Skoll.

"Looking back over the past three years, I'm incredibly proud of the work done by the team at Google.org to support wonderful projects and people," said Brilliant in a statement on Google's blog.

"These two organizations are neither competitors nor strangers, but rather friends and colleagues… in the coming months and years we can expand that relationship even more."

Dr Brilliant – a former World Health Organisation executive who has worked on a number of public health initiatives – will head the Skoll Urgent Threats Fund, a group supporting initiatives to solve problems such as climate change, water scarcity and pandemics.

The fund is the brainchild of Skoll, the billionaire founding president of eBay who now runs his own philanthropic organisation, the Skoll Foundation, as well as Participant Media – the behind campaigning films such as An Inconvenient Truth, Syriana and Good Night and Good Luck.

"This new organisation is designed to make serious headway on these issues by identifying and supporting the most innovative initiatives and solutions out there," said Skoll in a statement. "I can't think of anyone better prepared to shape and lead this effort than Larry Brilliant."

Dr Brilliant said he would remain an advisor to Google, where he has been overseeing its philanthropic efforts since being persuaded to take up the role of executive director in 2007.

In that time, the group has announced major projects focused on renewable energy and pandemic prediction, as well as hundreds of millions of dollars of investments in a wide range of other schemes.

However, earlier this year he stepped aside into an advisory role – handing to Google executive Megan Smith as the organisation started to rein in its focus a little (one insider explained it to me as trying to make better use of the skills and technologies that Google could offer up… others described it as making Google.org "more Googley").

When I interviewed him last year, Brilliant explained how he'd needed some persuasion to overcome his worries about joining .org in the first place.



"I'd be dishonest if I said I didn't have concerns," he admits. "I was particularly concerned at the impatience of engineers - especially because I've run internet companies. "I used to teach my students that their schemes wouldn't be successful until two things happened: that they would be able to run without you, and that you knew the names of the grandchildren of the people you started the project with: that's because it takes a generation."

There's no suggestion that any sense of impatience from Google has precipitated this change, but it's also clear that some of the subjects that really motivated Brilliant – the sort of big, global health challenges that he's taken on in the past – were not quite as a priority for Google.org as they were in the past.