If only there were people in the Philadelphia area that played it as actively as Warhammer groups play 40k. I've played it once, at a walk in match inside a nearby comic shop. No joke. A friend hit me up, and told me to come down to play Fleet Battles, since a guy brought in a huge set of ships, so that people could play. This was right after it launched, so there wasn't too much going on; but boy was it fun. Nothing like it has happened since, at least that I've known of, but I'm not a huge tabletop guy, so I'm really not in the know when it comes to any events in the area - plus, I don't seek it out actively enough to spot it anyway.
I will say, more and more people are hearing of HFB, and more groups are talking about it, and from what I've heard it's selling at a steady good pace, so I expect to see it more often in a year or two after some bigger expansions come out.