A web bug, also known as a tracking pixel or web beacon, is a small piece of code embedded in a web page or email that allows the sender to track user activity. These invisible bugs collect information such as IP address, browser type, and browsing behavior, which can then be used for targeted advertising, website analytics, and even email tracking. While they may seem harmless, web bugs raise concerns about privacy and data collection, as they can track users across multiple websites and platforms without their knowledge or consent.