According to this graphic anyway:
To better answer these questions, behold the “GeoSocial Universe.” The graphic below pits our social network usage against the huge adoption of mobile phones — currently at 4.6 billion worldwide.
Facebook, with over 500 million users, is still around 10 times smaller than the worldwide mobile market. Even web-based e-mail, which accounts for over 800 million users collectively, barely holds a candle to the mobile juggernaut.
I don’t suppose the trend is anything but increasing geosocial though.