Bazaarvoice Inc. announced today it will buy competing ratings-and-review technology provider PowerReviews Inc. in a transaction worth $151.9 million. The deal includes a cash payment of approximately $31 million and the transfer of up to 8 million shares of Bazaarvoice stock, currently trading at around $15.

Bazaarvoice expects to close the deal by July 24.

Bazaarvoice and PowerReviews are by far the dominant providers of customer ratings and reviews technology to the top 1,000 online retailers listed in the Internet Retailer Top 500 Guide and the Second 500 Guide. Bazaarvoice dominates among the larger e-retailers, with 159 clients among the Top 500 retailers to PowerReviews’ 80; no other vendor has more than 6 Top 500 clients. But PowerReviews, founded in 2006, counts more clients among the Second 500 retailers, 62 to seven for Bazaarvoice, founded in 2005.

“We are entering a new era where business growth is a direct result of your ability to connect with customers in the ways that are most meaningful to them,” says Brett Hurt, founder and CEO of Bazaarvoice.  “Together, our companies can create tremendous value for retailers and brands and help us to achieve our purpose of putting the voice of consumers at the center of their business. We are incredibly excited about the opportunity to work together with PowerReviews as part of the Bazaarvoice family.”

Today Bazaarvoice said its revenue for the fourth fiscal quarter ended April 30 will be between $31.0 million to $31.5 million, up 60.8% to 63.4% from the same period last year. Earlier this year, the company said it raised $116.3 million in its initial public offering.