There’s an old networking adage that everyone is worth meeting at least once. To find out if that’s true, try sending an open invite on Twitter the next time you’re alone in a strange city. “Just passing through Denver tonight. Who wants to have dinner?” It’s an introvert’s worst nightmare, but for a certain kind of hyper-networking traveler, it’s become the preferred way of turning downtime into business time (or, if things go really well, business time.) My “Cultural Studies” column in the Times, in which I ask these people why.