Tumblr has scant revenue and a nascent business model, but the fast-growing blogging service said it raised $85 million in venture capital. The investment values the company at $800 million, said people familiar with the matter.

The funding round highlights a continuing interest in promising new technology companies despite concerns about the economy at large. The Wall Street Journal reported last month that Tumblr was poised to raise $75 million to $100 million in a round that put the company at $800 million.

So...