It would be cool if you could set a schedule for certain times to block sites (or time limits). There are various browser extensions for this, but it would be more effective on the system level.
Most time-wasting sites never need to be accessed, though some of them are occasionally useful.
I think the app should let you access blocked sites when you need to, but make it difficult in some way. E.g. it could pop up with a warning and require user to enter a code. Often people waste time impulsively so a small block is enough to get them back to work.
(Alternatively, it could send out an email or post it online when a user over-rides a blocked site. Or it could fine the user!)
The issue is it's too easy to disable a Chrome extension, and then you need to re-enable to get it back. It would be better if they allowed you to temporarily over-ride it instead.
