I remember in Cambridge I could swing downstairs to the neighborhood bar, find a stranger, and strike up a conversation. Maybe it didn't work half as well as I am recalling, but even then, it was better than DC, where it always turns to "where do you work?" And "a startup" has only slightly more cachet than "I'm unemployed."
From a professional standpoint moving here has been great, but from a personal point of view, I think it's the biggest I've made.
I sometimes wonder if there is some kind of random stochastic effect that's related to where on the social graph you connect initially in a city that determines this outcome.
But I really, really tried. So did my friend, who was far more outgoing than me. Neither of us were able to meet very many people in Boston, or ever to feel comfortable there.