I'm not sure if something like this exists, but if it does, I'd really like to know about it. I was searching for a Twitter application with a feature to automatically respond to anybody who sent a direct message to your account. I know there's software that's capable of mass-messaging everyone, but that doesn't seem very targeted at all. Also, due to paranoia, I feel as if doing something like that would be much riskier. By responding to messages other people have sent, you'd be targeting an audience who is engaged with the direct-messaging system, and more importantly, they've actually recognized your account. Anyhow, does such an application exist? Preferably free, because I don't has money yet.