But I still feel like the first response, if it's possible, should be an email. We're just a couple of guys, and both our website and our game's credits make it clear that we're not a major faceless company.
I suppose people are conditioned by large companies ignoring them, so I hope that the proliferation of indie developers in the App Store can recondition people to actually send emails.
We love getting direct email from people, and we respond to every single one. I think people are sometimes surprised to get a personal reply; hopefully that won't be such a surprise if enough developers do it.