Rated 1 out of 5 stars

New version comes with search hijacker. Dude just wanted a simple calculator, Don't need you to hijack or "SUGGEST" me search results. As dumb of a move as I've seen. Stay away from this unless you want to have all your search results redirected to other "RELEVANT" sites. JUST WANTED A CALCULATOR

This review is for a previous version of the add-on (1.1.20.1-signed). 

SmartLinks is not a search hijacker. SmartLinks is an opt-in service that provides links to sources such as wikipedia. It is not required to run calculator and is only installed if you click the Accept button on the SmartLinks opt-in dialog. At any time if you change your mind you can remove it by going to the Firefox -> Tools -> SmartLinks menu and disabling or removing it.