Hoping to boost its Internet power, Microsoft has bought Greenfield Online Inc, the owner of European price comparison site Ciao GmbH, for about $486 million, the company said in a statement.

The price of $17.50 a share represented a 1.4 percent premium over the previous closing price, but was 32 percent more than Greenfield was worth when it withdrew from a deal with Quadrangle Group LLC for $15.50 a share two weeks ago.

The deal for Munich-based Ciao marks Microsoft's first major purchase since the demise of its $47.5 billion takeover bid for Yahoo in May. Microsoft had seen that purchase as a short cut in its attempts to compete with Google's dominance in web traffic and advertising.

Ciao provides consumer reviews and ratings along with prices from online merchants, and will be integrated with Microsoft's Live Search platform. The company makes money by earning commissions when customers it refers buy goods.

Ciao operates sites in seven major European countries and languages. It also recently launched Ciao.com, a beta site aimed at the US market.