The Silicon Valley (Brisbane) comparison shopping company Shopping.com has just announced that its CEO Dan Ciporin is stepping down, and that Lorrie Norrington, a member of the Shopping.com board of directors, will replace him June 1.

When you stock performance since going public last year looks like this ($16.78, down from around $35), something is bound to happen — especially in a sector that’s supposed to be growing. Apparently, Ciporin had been wanting to move back to the East Coast for some time — although the announcement doesn’t give any official reason for the CEO-switch. Ciporin will stay on as chairman. Wish we had more transparency in the revenue/profit numbers of the other major comparison shopping competitors, Bizrate and Nextag. Both are privately held, and say they’re profitable, but it’s hard to know how much damage they’ve been doing to Shopping.com’s market share. The traffic and user survey data seem somewhat volatile and unreliable. Yahoo and Google have also stepped up their shopping comparison efforts over the past year.