Actions are pieces of code you want to execute at certain points in your code. Actions never return anything but merely serve as the option to hook in to your existing code without having to mess things up.
Filters are made to modify entities. They always return some kind of value. By default they return their first parameter and you should too.
This project is a fork from Eventy for Laravel. The difference is that this project supports PHP 5.4 or later and it doesn't have any dependencies. Also, there are some differences in syntax.