The acquisition is the industry's third major deal in a week involving one of the world's largest hosting providers:

• On Friday investment firm GI Partners said it purchased The Planet and EV1Servers, the two largest dedicated hosting specialists in the world, according to Netcraft's Hosting Provider Switching Analysis.

• On May 2, start-up Demand Media Inc. revealed it had bought domain registrar eNom Inc., the third-largest domain registrar and also the world's fifth-largest web hosting provider with nearly 750,000 active sites and 1.3 million hostnames.

United Internet provides web services through 1&1 Internet, domain registrar Schlund + Partners, web portal operators Web.de and GMX and domain auction house Sedo. The acquisition also gives 1&1 a much larger presence on the Windows hosting platform. 1&1 hosts more than 90 percent of its sites on Linux, while Fasthosts is one of the hosting industry's largest users of Windows web servers.