Curious to see where you would have met Jason C.? He has 0 Foursquare checkins, perhaps you were at some of the same places too.
Allow Intersquares to connect to your Foursquare account, and you'll find out (here's a screenshot of what an intersection looks like).
Don't worry, we won't update your status or otherwise mess with your checkins.
Intrigued by the idea, but don't want to intersect your checkins with Jason's? Go to the homepage to generate your own link.