SingleFeed currently supports 17 comparison shopping engines that represent roughly 90% of all comparison shopping engine traffic: Amazon Product Ads, Become.com, Google Base/Google Product Search, NexTag, PriceGrabber, Pronto, Shopping.com, Shopzilla, Smarter.com, Sortprice, TheFind, Yahoo Shopping (via Pricegrabber), Shop.com, MSN Live Search cashback, MSN Live Product Seach, Like.com & buySAFE Shopping. 

We will be adding more engines in the near future. We want our clients driving our product, so please tell us which engines you'd like us to support. Post your request in our Feature Request / Ideas Forum: http://support.singlefeed.com/forums/131489-feature-requests-ideas