A 1 pixel-by-1 pixel image tag added to an HTMLmessage and used to track open rates by email address. Opening the message, either in the preview pane or by clicking on it, activates the bug and sends a signal to the Web site, where special software tracks and records the signal as an open. Webmail (also Web mail)
The 3 Things To Avoid When Emailing Your List
When you decide to have an opt-in list, it is not just a matter of sending your subscribers your promotional newsletters or catalogs.
