A beacon — also called a web beacon or web bug — is an HTML-embedded object that tracks user behavior on a web page. The beacon operates similarly to a cookie, except it’s usually an embedded image and is very tiny or entirely invisible to users. Beacons communicate statistical information back to a web server.
Email marketers can use beacons within email messages to track whether recipients read the email. The beacon sends that data back to the server. Other common uses for web beacons include:
- Online ad impression counts
- Ad campaign performance
- File download monitoring
- Read receipts on emails
- Third-party tracking
Similar to disclosures about cookies, sites must transparently explain to end users what web beacons are so the end users understand what data the site collects. The W3C has published a document to standardize beacon function so you can ensure that beacons don’t negatively impact your site’s performance.