Does what it advertises however I have a few gripes (this is feedback for 0.4pre5):

- after installing, it requires a page refresh to hide the comments
- there's no placeholder; sometimes I scroll down and forget the comments are blocked and wait for them to load (YouTube by default shows the same white space for a few seconds, even without the extension). Some text like "No comments here :)" would be helpful to remind me the comments are blocked
- also there's a typo :P "Prefrences" should be "Preferences"