British entrepreneur Sir Richard Branson has joined Greylock Partners and Insight Venture Partners in an $85 million (£54 million) venture capital funding round for blogging platform Tumblr.

British entrepreneur Sir Richard Branson has joined Greylock Partners and Insight Venture Partners in an $85 million (£54 million) venture capital funding round for blogging platform Tumblr.

New York-based Tumblr also secured the support of the Chernin Group in the fundraising deal, which values the business at $800 million. Previous investors Spark Capital, Union Square Ventures and Sequoia Capital also joined the round.

Tumblr chief executive David Karp launched the platform in 2007 as a then 20-year high school dropout. He has since grown the service, which now publishes more than 30 million blogs that attract 13 billion page-views a month, up from two billion at the start of the year.

According to the investors, the business generates little revenue, but they say they are ‘confident’ profits will follow in light of the large user base.

‘You will see some experiments later this year and early next year,’ Bijan Sabet, a general partner with Spark Capital and Tumblr director, tells reporters. ‘We believe you can build a successful revenue model against that.’

John Lilly, a partner at Greylock Partners and former CEO of Mozilla, writes on the firm’s blog, ‘What we didn’t know when we started, but learned as we went is that in addition to the ubiquity of Tumblr today, the engagement of users and posters and rebloggers is absolutely off the charts.

‘Good content gets surfaced and spread incredibly rapidly — more quickly than any other network I’ve ever encountered. Lots of reasons for this incredible engagement — the team at Tumblr has done a wonderful job of figuring out some fundamental and novel avenues for self-expression.

‘I’ve found so many interesting posts and perspectives on Tumblr that I never would have found without it — and it’s clear that that’s been the experience for millions of other users.’