Android notifications are powerful -- so what if you could connect them to the Web and make them even more robust?
With the help of Pushover, you can. Pushover lets you set up various custom notifications based on things that happen online. It uses a service called IFTTT (short for If This Then That) to do its magic.
There's a huge list of Pushover-ready-to-use recipes for the taking: You can have the app notify you anytime a particular server goes down, for instance, or when your Amazon orders ship, or when tracking info is updated for a package you're expecting.
Pushover costs $5.