Sunnyvale-based Retrevo, which operates a service to help find reviews and manuals on electronics products, has linked with comparison shopping firm PriceGrabber.com. According to the two, PriceGrabber will feature Retrevo's reviews and other information on its site, and Retrevo will feature PriceGrabber's comparison shopping information on its own service. Financial details of the deal were not disclosed by the firms. Retrevo is backed by Alloy Ventures and Northwest Venture Partners.