CEO Jim Lanzone is resigning after six years with the company, to join a venture-capital firm. His replacement, Jim Safka, is currently head of Primal Ventures, the venture-capital division of's parent company, IAC.

Barry Diller, CEO of IAC, said the moves are intended to streamline the operating structure of IAC as it prepares to spin off some of its operations.

The group plans to turn its HSN (Home Shopping Network), Ticketmaster, Interval International and LendingTree operations into separate, publicly traded companies.

Lanzone has been responsible for a turnaround at over the past two years, Diller said in a statement.

However,'s share of the U.S. search market is small: it had just 4.6 percent of the market in November, compared to 9.8 percent for Microsoft, 22.4 percent for Yahoo and 58.6 percent for Google, according to market watcher Comscore.'s share has fallen from 5.2 percent in March, according to Comscore figures.

In November, however, Ask struck a deal with Google said to be worth up to $3.5bn to display sponsored search listings for its larger rival.

It has also tried to differentiate itself from the other search engines by promising to protect its users' privacy and erase personal data stored about the searches they make.'s new CEO Safka will be aided by Scott Garell who, in the role of president, will manage's daily business operations. Garell is currently head of IAC's consumer applications and portals business, which includes the Evite service.

Ex-CEO Lanzone become an entrepreneur-in-residence at Redpoint Ventures. That company's past investments include Excite, MySpace, TiVo - and itself.