I've never had a single person reply to anything I've sent through dancepartner dot com's basic (free) system, not even to say "sorry no thanks."
I once wrote up a very detailed message outlining my dance interests, level, and goals, and some ideas of what kind of training I'd want to do as a partnership (including what I was firm about and what I was open to being flexible about). I joined the "gold" level for a month so anyone, including free members, could respond. I sent this message to about 12 guys and got four responses, all quite genuine. Two had changed the focus of their dancing since they had put up their profile (one had gotten sucked into the vortex of AT ) and the other two were willing to meet for tryouts. They didn't work out for various reasons, but I don't consider the experience a failure.