A tracking blocker is software or browser settings which limit programmatic trackers from capturing and recording a user's online activity.
Most websites track visitors, clicks, pageviews, and often use 3rd party tracking tools to personalize site experience or target ads to consumers based on past web history and visits. This tracking occurs without visible indicators, and most online users never know when they are being tracked or the full extent of it. As ad retargeting has gotten more precise, consumers have become concerned at just how quickly advertisers know their every online step.
Users are also concerned that a data storage breach of this accumulated information could result in their personal online history or sensitive data being exposed.
Tracking blocker features can include hiding user search queries, anonymous web surfing, sending do-no-track header information, deleting third-party cookies, hiding a user's IP address and more. Blocking the tracking information can have a substantial impact on publisher ad eCPM, since brands pay a premium for ads targeted to specific user segments.