This extension does NOT effectively or accurately do what it claims -- the exaggerated claim masks what it really is: A universal tracker and data collection app for everything you see and do with Firefox. You have to provide an email address to use it! I ran a test based on a purchase I made the day before: I found a specific SSD drive on Amazon with their best price of $74.50 but then looked around and found it on Ebay for $68.00 and bought it there. So today, after installing this extension, I ran the exact same purchase test on Amazon: After the $74.50 price came up on Amazon the Capital One Shopper did NOT pop up with the price of $68.00 on Ebay (or anywhere else).

The access permissions for this extension enable it to collect your PERSONAL, NON-ANONYMOUS data on absolutely EVERYTHING you do in Firefox in real time from all open tabs and searches. Then, by its own admission, immediately sends this personalized data back to Capital One for their use and storage (and ostensibly so they can find you "like, the absolute bestest price EVER!") Sure the user agrees to this during installation, but how many people realize just how invasive it is and that it really does not do what it claims very well? This extension crosses the line into serious privacy abuse and seems like it may even present a security vulnerability to the Firefox platform.

Do not install it and open the account they require for it to operate "just to give it a try" because the second it becomes active in your Firefox it will immediately grab everything it can find and send it to Capital One with your name and email address on it. And they don't let you change the email address you give them when activating the extension.