comScore has released its Media Metrix rankings for the top 50 web properties in the U.S. in July.

And here they are:

Google sites were up from last month, at over 190 million unique visitors in the U.S. compared to 168 million for Microsoft sites, 162 million for Yahoo sites, and 160 million for Facebook.com. Yahoo actually lost traction, as last month, it was beating Microsoft (167 million vs. 166 million). Facebook remained relatively unchanged.

Here are the ad ecosystem rankings:

Instagram topped the list of top gainers, followd by Sun Microsystems, PriceGrabber and Valve:

“Millions of Americans visited the Business and Finance category in July for up-to-the-minute reporting on the unsteady financial markets and for a mid-year health check on their investments and other financial interests.” said Jeff Hackett, executive vice president of comScore. “With summertime leisure also in full effect, many others took a more laid back approach to their web browsing by visiting community-based interest sites, including Pets and Beauty/Fashion/Style sites.”

Surprised by anything on the lists?