Ask Jeeves co-founder David Warthen has joined citizen journalism-meets-mainstream journalism site Allvoices as Chief Technology Officer. He will be responsible for the technical direction of the company.

Warthen previously served as CTO for several other companies including social Q&A site AnswerBag, which was second in its space only to Yahoo Answers, and was eventually acquired by Demand Media (sidenote: an interesting deal between AnswerBag and MerchantCircle was recently made). It will be quite interesting to see where he takes Allvoices. If you’re unfamiliar with Allvoices, read our recent interview with CMO Aki Hashmi about just what the company is doing for the news industry.

"I am delighted to be joining Allvoices, which is leading the transformation of the news industry toward citizen journalism by pushing the state-of-the-art in using self-regulating, scalable, and social technologies," says Warthen. "It is exciting to be part of such a significant and transformative effort. At Allvoices, news itself is being redefined from a top-down editorially controlled activity to a bottom-up massively social activity, which includes coverage of many topics and perspectives that are ignored in the old model."

"David brings tremendous value to the company, and we’re excited to have him on board to lead our outstanding engineering group," says Amra Tareen, founder and CEO of Allvoices. "David has been at the forefront of several groundbreaking technology innovations, and his skills and expertise will further strengthen Allvoices."

Under Warthen’s technical leadership, Ask Jeeves became one of the top Internet search engines in the world just 18 months after the site launched in 1997. The company was acquired by InterActive Corp (IAC), run by media mogul Barry Diller, for $1.85 billion in 2005 and was of course rebranded as Ask.com.