I’ve become a big fan of notifo recently - which is essentially an iPhone app that serves as a central ‘ping’ location for developers to send notifications without resorting to email.
It’s kind of similar to Amazon’s new Simple Notifications Service - but so far to me a lot more practically useful, and certainly a much better API
I made a small service for notifo called ‘Converto’ - basically whenever you get a ‘conversion’ via a link, you can be notified on your iPhone. Currently I use this service whenever someone starts using tweetbe.at, I get a ping on my iPhone.
Notifo is also very useful to me for letting me know when someone mentions @alexbosworth on Twitter, or when someone responds to my comment on hackernews