I'm curious how people are finding, and then using your service. Are most of the users people who use another app that provides pushover notifications, or are they developer or power user types who want a way to push notifications to their phones? (I would assume the former, I suppose.)
Most are sending alerts to themselves. While I've integrated it into Github and my Fitbit notifier to try to pick up users that just want to receive alerts, most are using it to generate their own alerts from network monitors, BitTorrent clients, IRC clients, etc.
I pinged the ifttt.com guys to ask about integration but haven't heard back yet. I'd like to do more integration with services that currently do e-mail notifications like http://hnnotify.com (I've already contacted them) to pick up more end-users.