Launched in 2004 by then 27-year old Kevin Rose, Digg rose to prominence as an aggregator of online content, becoming at one point one of the more highly-trafficked stops on the Internet. The site let users vote up - or "Digg" - links, an early precursor to how Facebook and Twitter help spread "viral" content today.

The deal was worth just $500,000, the Wall Street Journal reported.

The sale came after the majority of Digg's engineering staff left in May for Social Code, a subsidiary of The Washington Post Co.

"Over the last few months, we've considered many options of where Digg could go, and frankly many of them could not live up to the reason Digg was invented in the first place -- to discover the best stuff on the web," Digg Chief Executive Matt Williams said in a blog post. "We wanted to find a way to take Digg back to its startup roots."

Digg's website will continue to exist, and Betaworks will soon launch a new "cloud-based version of Digg" to complement its current offerings, Williams wrote.

Still, Thursday's acquisition drew the curtains on a start-up once feted in Silicon Valley.

The company raised a total of $45 million in funding from established venture capital firms like Greylock Partners. In 2006, Rose starred on a well-known BusinessWeek magazine cover, flashing his thumbs next to the headline: "How This Kid Made $60 Million In 18 Months."

(Reporting By Gerry Shih; Editing by Tim Dobbyn)

• A Permanent Economic Emergency