Probably the best add on for Firefox if fanfic is your jam, and to second another, a mobile Firefox version would be amazing.

Works exactly as expected. I especially like the author/tag/language filters, and the interface for adding them. It is a very useful extension for blocking these.
The interface is very easy to use, and it looks very nice too, aesthetically.
I will definitely keep using this extension.

Wonderful, absolutely crucial extension! I won't lie, I'd kill for a firefox mobile version, though :P