Less than a week after eBay announced it would buy Shopping.com, another comparison shopping site has been snapped up. E.W. Scripps just said it's buying Shopzilla, known until recently as BizRate.com Inc., for $525 million. The funny thing is that so far, the traditional Internet portals haven't been the acquirers, even though many observers think thought they would be.

In fact, Gary Little, a venture capitalist with Morgenthaler Ventures who invested in NexTag, another shopping site, told me Friday that he thought all the major portals would add comparison shopping if they haven't already. "There is definitely an opportunity for a comparison shopping site to be independent," he said.

Maybe. But I'm more doubtful than ever now. I know relatively few people who know about these sites, let alone visit them regularly. The sites rely to varying degrees on buying traffic on Google or running Google ads or both. You have to wonder why Google, which has a related shopping site called Froogle, won't eventually short-circuit that loop--that is, if portals like Yahoo! or left-field entries like Amazon's A9 search site don't do it first. In which case, this feeding frenzy may end as quickly as it started.

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