WASHINGTON – U.S. Rep. Joe Barton of Texas, the House Energy and Commerce Committee’s ranking Republican, today wrote to Yahoo! CEO Jerry Yang about the company’s recent advertising partnership with Google.

“Given the consolidation within the online advertising industry, and with three companies dominating the U.S. online search market, I am concerned about how this collaboration will impact competition within the online search advertising industry,” Barton wrote. “I am also concerned about how the relationship between Google and Yahoo! will affect the collection, storage, and use of data relating to an individual’s online activity.

“The potential for this data to be shared or merged and, perhaps, used in ways that Google or Yahoo! users may not have anticipated raises a number of questions about consumer protections and privacy,” Barton added.

Barton began his inquiry when he wrote to Google Chairman and CEO Eric Schmidt in December 2007 about privacy issues raised about the now-final merger of the search engine Google and DoubleClick, the Internet advertising giant.

A copy of the letter can be found here.