According to a new report from Forrester Research published on Mashable today, the number of Social Networking Users Has Doubled Since 2007. Of course, this is limited to the US, and it still doesn’t put social networking in the top spot in terms of how adults use the internet. In fact, the report puts “using email,” “sending and receiving photos via email,” “researching products for purchase,” “purchasing products” and “watching internet video/streaming” above social networking use in terms of proliferation amongst the US adult population.

Still, 55.6 million social networking adults is nothing to sniff at.

And the beauty of this chart is that Ranker actually provides a platform for users to engage in pretty much every activity on  it, so there’s even something for the non-social-networkers (whoever they are).

Of course, some things (streaming audio, instant messaging) are currently gestating in the development womb. But, our system is flexible enough to provide for all of these possibilities. Which means that we can cover even those users who don’t make it into the 1/3 of the US population who regularly use social networking sites. And nothing makes lunchtime a lil’ bit sweeter quite like validation in the form of pretty charts and stats.

So, Mashable, I raise my PB&J in thanks to you for printing this story just in time for lunch. Just don’t expect me to share my cheez-its.