As a long term user of the LeechBlock add-on, I was really amazed by simplicity and ingenuity of Intention. Intention delivers the best productivity features in a simple package. Easy to setup, easy to use, does its job well without need for additional tweaking. Now I can have YouTube effectively blocked for mindless browsing, while still comfortably use it for listening to the music. Thanks to Intention, I can also accesss Facebook Messenger for a minute to quickly reply to my student, but having it effectively blocked for long-term chat sessions with my friends and family. Brilliant UX design.