Neat. However, installing ZNC on your own an Amazon EC2 micro instance is cheaper.
You're paying [a very small amount] to IRCRelay for convenience and not having to worry about it. At least for my close friends, they'd rather pay $5 a month than deal with setting up an EC2 instance or VPS to do this for them.
- screen and irssi is a far better experience than using a bouncer. Perhaps offer that? These services, back in the day, used to be "shell providers" for this reason.
- Most developers I know run their own VPS and probably wouldn't consider a service like this.
- I happily pay $20/month for my Linode wherein I do this, the big reason being I can also torrent, compile, host quick Internet stuff, do development work, receive mail, etc.
Administering a personal development machine is a gateway to becoming a better hacker these days, so I think you'll find that your market ends up being miscreants who have $5 to throw away on a throwaway bouncer to cause trouble.
I definitely agree with your last point - the "irc types" also tend to the the "hacker types" these days.
I think my micro instance was $54/yr, and like you mention, I can do a lot more with it.
I'm very open to it, if it can be done in a safe way. One way to do this may be to just curate a set of ZNC modules (since there aren't tons) that are approved to be installed, such as your znc-push module. It looks like that sort of thing would provide a lot of value.
I run irssi in tmux on EC2 with a Colloquy push script (http://static.ssji.net/colloquy_push.pl.txt). Spent time trying to get it right, but Colloquy is flaky at best.