World's Largest Mobile Social Network

Instagram it is. We had spotted some instagram statistics before - we spotted this today:

Image Source: Socialnomics
"Since Christmas the mobile photo network Instagram has gained over ten million users. This makes Instagram the largest mobile only social network with a global reach.
Foursquare by comparison is on around 22 million.
Instagram hasn’t officially announced these figures, and they aren’t published anywhere else as far as I can see."

Statistics Source: Lies, Damned Lies and Statistics

Put this into context - we know there are more smartphone users than other mobile phone users in the U.S. We also know that there would be about 1 billion smartphones shipped by 2015. 25 Million is not huge - but it is definitely not small either.