Walmart.com Chief Marketing Officer Cathy Halligan said in an interview the retailer decided to launch the new feature quickly following a three-week testing phase in which it received more than twice the number of reviews it was expecting.
"It is the No. 1 customer-requested feature," she said of reviews and ratings.
Wal-Mart, the world's largest retailer, has been working to integrate its Web site more closely with its stores.
The launch of the new function comes a week after Walmart.com completed the roll-out of its "Site to Store" program, which allows customers to order products on its Web site and have them shipped to a local Wal-Mart store for free.
The shipping program is helping in-store sales, with Wal- Mart saying it has seen an increase in the number of "Site to Store" customers spending an additional $60 in its stores when they pick up their orders.
In adding the rating and review feature, Wal-Mart joins a growing number of Web sites, including Amazon.com, that allow users to post merchandise critiques. The reviews are seen as a way to increase shopper loyalty and encourage consumers to return to a Web site more often.
Halligan said that during its testing phase, most of the reviews it received gave products high ratings--4 or 5 stars. Five stars is the highest rating, while 1 is the lowest.
The two top-rated products to emerge from the test were a Garmin Nuvi 350 portable global positioning system navigator, which is listed on its Web site for $369.54, and an Emerson 32-inch LCD TV that is listed at $538, she said.
Wal-Mart estimates that roughly 130 million customers visit one of its stores or its Web site every week and it said 75 percent of those customers are active online.
"We are not planning any specific sales acceleration as a result of launching this feature," Halligan said. "But one could expect that providing our customers with the No. 1 requested feature and something that connects 130 million people to each other has got to accrue benefits."
In the future, Halligan said Wal-Mart could interact with customers who post reviews and the reviews could be used to make decisions on which products Wal-Mart sells.
"We will use those customer reviews and ratings to be able to provide more direct information about how our customers feel and make decision on a case-by-case basis," she said.
When the feature officially launches on Thursday, Halligan said Walmart.com will publish the reviews it received during the testing phase.
She said that, when a customer submits a review, it will be posted five to seven days after being screened to ensure it does not contain inappropriate language or copyrighted material.