Microsoft Corp. is buying a Munich, Germany-based Web comparison shopping site and its parent company for about $486 million in cash.

The Redmond, Wash.-based software maker says the acquisition of Greenfield Online Inc., which owns Ciao, a collection of European price-comparison, shopping and consumer reviews sites in seven countries and languages, will boost its search presence in Europe.

The company says the Ciao sites get more than 26 million unique visitors a month and so far has generated more than 5 million product reviews.

Greenfield shareholders will get $17.50 a share, Microsoft said Friday. The transaction is expected to close during the fourth quarter of 2008.

Microsoft lags market leader Google Inc. in search traffic and Web advertising revenue. In recent months, the company has focused on improving its sites for searches that lead to shopping and travel.