Notifo.com is a web service which enables you to send push notifications to your mobile device (at the moment there is only support for the iPhone). This blog post first called my attention to the service. I have used prowl (a similar service based on growl) before and I was instantly interested in this somewhat more versatile notifo.
On the same evening I decided to build a python library, to be able to easily notify users from python applications. I also thought it would be cool to get push notifications from your CI server about your builds. So I implemented an integrity notifier which is now available in the main line.
At the moment I personally use notifo to get notified about twitter mentions via push.ly, website changes via femtoo and commits to some of my github projects via a service hook. Once I have found suitable hosting for integrity for my projects, I will also use the integrity notifier. And I am very excited to see what else will be build upon this service.