Pushbullet is a great way to get push notifications in your browser and on your phone . Now Pushbullet has an If This Than That channel so you can push customised info right to your Android or iOS device.
Pushbullet is essentially a way to easily send information between your computer and phone. The IFTTT integration means you can automate that process and set up custom notifications for anything that works with IFTTT.
For example, you can set up a notification to alert you when a friend checks in nearby on Foursquare, someone on your calendar has a birthday, when a specific user posts to Instagram, amongst many others. It's still a new channel, so we'll have to wait and see what happens with it, but it could make creating custom notifications a lot simpler.