Content-sharing site Digg has sold to Betaworks, and the technology investment company grabbed the waning social starlet for only $500,000, according to The Wall Street Journal. Of course Betaworks is only really acquiring Digg’s technology, with founder Kevin Rose having left the company last March and Google having hired him this past March and The Washington Post-owned social marketing firm SocialCode picking up a slew of Digg engineers in May. Betaworks plans to return Digg to its startup roots, specifically aligning it with the company’s Facebook-and-Twitter curation ap...