This is one of the best site blocking apps for Firefox. I can't resist browsing news sites at work. The sites were leeching my time.
With this app installed, I can work with full focus. Thanks Devs.

This is really really really good

Improves my productivity at work.

can block keyword... this is a 100% useful feature

Really really good for productivity. It makes it so easy to stop habitually checking a website.

Does what it says. Solid.

Does what it says it does on the box. I really like the customizeability, and the delay pages are great for giving me those two minutes to think about if I really want to go somewhere.

It does what it's supposed to do and it does it good!

Useful little plugin that helps keep you on task. It has the awesome feature of being able to set different amounts of time for different groups.