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

And here they are:

Google sites saw 189 million visitors, compared to Yahoo’s 167 million, Microsoft’s 166 million, and Facebook’s 160 million.

Here are the ad ecosystem rankings:

The list of top gainers from month to month is pretty interesting. For one, Zynga managed to double its unique audience in the U.S. in that time. Mozilla put in a pretty impressive showing in that category as well:

“June got off to a strong start with significant traffic gains seen at Travel and Retail sites as Americans readied their free time for the long-awaited summer months,” said Jeff Hackett, executive vice president of comScore. “With more leisure time for game playing on their hands, nearly 15 million people visited Zynga in June, representing a 103-percent gain to rank as the top-gaining property.”

Are you surprised by any of the rankings?