Microsoft ranks as the top U.S. parent company, with more than 121 million home and work online unique audiences and an average two-hour time spent per user, according to the latest Nielsen//NetRatings report on July 2007 data for top sites by parent company and top brands.

Google was ranked number two, with Yahoo!, Time Warner, News Corp. Online and eBay following.

In terms of the top 10 U.S. brands in July 2007, Google was at the top, with nearly 112 million unique users and an average of one hour spent per user. Yahoo!, MSN/Windows Live were at the second and the third, both with more than 100 milion unique audiences.

According to Nielsen//NetRatings' definition, a parent company is “a consolidation of multiple domains and URLs owned by a single entity.” A brand is defined as “a consolidation of multiple domains and URLs that has a consistent collection of branded content.”