Microsoft has reheated a market many web watchers had assumed a busted flush with the acquisition of Jellyfish.com, the bastard child of a shopping comparison site and QVC.

It's one of a crop of sites that offer shoppers cashback for buying from its affiliate merchants, who can decide how much to pay to the site by way of commission. As well as product searches, it runs reverse auctions in the style of a TV shopping channel, where the steeliest bidders can pick up a bargain.

The LiveSearch crew wrote: "We think the technology has some interesting potential applications as we continue to invest heavily in shopping and commerce as a key component of Live Search."

It's likely that Redmond is most keen on Jellyfish.com's advertising back-end, which it claims protects against click fraud. It operates on a "pay-per-action" basis, rather than "pay-per-click", meaning users have to spend before the advertiser pays the site. Google is trialling a similar new model for its AdWords system.

Google pretty much gave up on shopping comparison itself as a damp squib earlier this year when it cut off Froogle's oxygen supply, instead sharpening its e-commerce talons for its PayPal competitor, Google Checkout.

At time of writing the Jellyfish.com site is unavailable. Financial details of the deal have been kept secret. ®

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