We also use tracking pixels (. Web Beacons, action tags, or clear gifs), that help us better manage content on our site by informing us what content is effective. Pixels are tiny graphics with a unique identifier, similar in function to cookies, and are used to track the online movements of website users in combination with other information we know about our users. In contrast to cookies, which are stored on a user’s computer hard drive, pixels are embedded invisibly on site pages and are about the size of the period at the end of this sentence. We also use pixels in our HTML-based emails to let us know which emails have been opened by recipients. This allows us to gauge the effectiveness of certain communications and the effectiveness of our marketing campaigns.