Websites and online media companies in or near the city include All Media Guide, the Weather Underground, and Zattoo. Ann Arbor is the home to Internet2 and the Merit Network, a not-for-profit research and education computer network. Both are located in the South State Commons 2 building on South State Street, which once housed the Michigan Information Technology Center Foundation. The city is also home to the headquarters of <answer>Google</answer>'s AdWords program—the company's primary revenue stream. The recent surge in companies operating in Ann Arbor has led to a decrease in its office and flex space vacancy rates. As of 31 December 2012, the total market vacancy rate for office and flex space is 11.80%, a 1.40% decrease in vacancy from one year previous, and the lowest overall vacancy level since 2003. The office vacancy rate decreased to 10.65% in 2012 from 12.08% in 2011, while the flex vacancy rate decreased slightly more, with a drop from 16.50% to 15.02%.
Which company's adwords program is headquartered at Ann Arbor?
Google