CPC_Andrew - 2:16 pm on Jun 4, 2012 (gmt 0)
@trinorthlighting Bing Shopping has a partnership with Shopping.com so if they can they'll show a paid listing at all costs.
One thing to consider here is the affiliates and crappy sites that get thrown up, pasted together with a shopping cart and start submitting their products to Google. Many of those guys will be left out of the loop here. Since they won't be able to provide a satisfactory user experience (weighted in the new Google Shopping SERPS) nor will they want to pay for and manage traffic to their stores, there will potentially be a greater opportunity in terms of sales volume for merchants with good standing who get in front of this opportunity.
Google Shopping is becoming another shopping.com, the PLA program is exactly like a paid comparison shopping engine. Bids can be based through identifiers in the feed, commonly product, brand and category, though you can optimize bids by condition and other attributes. It will not be a keyword or ad-copy run ad channel. So be weary if you have a SEM firm who's eager to jump in here.
If they don't have experience with data feeds or bidding at the product level you're going to be in for a bumpy ride...