Avoid this kind of extensions that can collect what you are looking on the internet, it's just collecting informations on you to profile you and similar customers to target ads/products/services. That's desguished spyware in counterpart to provide you a pretended nice service.

And just about the service provided: this kind of extensions (lots of similar exist like this one) can modify the webpages on-the-fly and also can censure some parts or search results to guide you to buy to a specific seller instead of a concurrent. And guess who is paying the extension editor to do that?

Mind again before addin browser extensions!