Google's metashopping search, Froogle, adds merchant reviews. The reviews seem to be spidered off other sites. For example, merchant reviews for Buy.com were from Bizrate, Shopping.com, and PriceGrabber.
There doesn't appear to be any way to enter your own review. That's too bad. Building a catalog of authoritative and trusted merchant and product reviews would make Froogle more compelling and would be a great differentiator. One of eBay's strengths is in being able to see the reputation of sellers, a type of merchant review. One of Amazon's advantages over other online merchants is the quality and depth of its product reviews. If Froogle is serious about helping people shop, it needs to help people find authoritative and reliable reviews.
Speaking of merchant reviews, there's still no merchant reviews on Google Local. Yahoo Local does have merchant reviews.
Merchant reviews will be a key feature for local search. It's hard to get authoritative, reliable reviews of local merchants. Services like Citysearch, ePinions, or Zagat attempt to provide reviews, but coverage is spotty and reliability uncertain. A well implemented local search with merchant reviews could change this space forever.