I was going though rating and reviewing my add-ons, and was surprised to see the concerns regarding Google Analytics and facebook as posted by some. I was shocked to read this, and even more so shocked to see it for myself. I put off my review until I contacted them, and had this explained to me: "We use Google Analytics and have Facebook like buttons (and other widgets) on our website like most other websites in the world. You are not exposed to either of these by just using the add-on, only if you visit our website."
I can say that I feel much better about this now, and can continue to give this add-on a full 5 star rating, without hesitation. I consider this to be one of the essential add-ons on any browser.