Microsoft said Friday that it has reached a deal to acquire Greenfield Online, operator of the Ciao shopping and price comparison sites, for $486 million.

Ciao's Web sites let users search for and buy a wide range of tech products while comparing prices from numerous online retailers. It operates sites in seven major European countries and languages. Ciao also recently launched Ciao.com, a beta site aimed at the U.S. market.

Ciao users can rate products, provide feedback and create lists of their favorite gadgets and appliances. Microsoft officials said the sites would be integrated into its Live Search portal in Europe, where Ciao is most popular.

"Integrating Ciao's capabilities into Live Search will provide a strong launch pad for our commercial search offer in Europe and enhance our e-commerce offering on MSN," said John Mangelaars, VP for consumer and online products at Microsoft's European operations, in a statement.

Overseeing Ciao's operations at Microsoft will be Rajat Taneja, the company's general manager for worldwide commercial search. Microsoft also plans to open a European search technology center this year.

Microsoft is looking to increase its share of the paid search market, where it trails Google and Yahoo. Its attempt earlier this year to acquire Yahoo having been rebuffed, the company is now eyeing smaller, tactical targets.

In July, Microsoft bought out Powerset for a reported $100 million. Powerset specializes in an esoteric form of Web querying called semantic search. The technique uses a variety of linguistic tools to interpret the meaning of search phrases to produce the most accurate results. The method has been in development for more than 10 years.

Earlier this year, Microsoft bid $1.2 billion for Fast Search & Transfer, which lets business users sift through corporate databases for structured and unstructured information.