Gmail opened to residents of the entire planet on February 14, 2007. Prior to this, Gmail was in beta testing and it was possible to register only by invitation from other users of the service. If you believe the statistics
Hitwise , the share of Gmail in the US market from February to April 2007 increased by 17%, and from April 2006 to April 2007 - by 30%.
Yahoo! Mail and
Hotmail still dominate mail services and at the moment their market share is higher than Gmail by 13 and 6 times, respectively.

Gmail users are different from the average Yahoo! Mail and Hotmail. So, Gmail account owners are probably younger, have more income, live in large cities. So, in four weeks (until April 28, 2007), 54% of Gmail visitors were between 18 and 34 years old, while Yahoo! Mail and Hotmail, the figure was 42% and 44%, respectively. As for income, 18% of Gmail users have an average annual household income of $ 100-150 thousand, against 15% for Hotmail users and 13% for Yahoo! Mail. In addition, Gmail users most often live in large cities (U1) and suburbs (S1-S2).
