Glossary

301 redirect A server setting that redirects traffic from one URL to another while sending a 301, or “permanent,” status code to the requesting client. Also called permanent redirect. See also client.

404 error The error returned by a web server when a requested file cannot be found. Also called File Not Found error.

A

A/B split A method of comparing the performance of two sponsored listings, landing pages, or other online content. Also called A/B testing.

A/B testing See A/B split.

acquisition source See traffic source.

Ajax Short for Asynchronous JavaScript and XML, a scripting technique that allows web applications to interact with the user and render changes to a web page without reloading the page. With Ajax, the user may have an experience that feels like visiting several different pages, while the page URL remains the same throughout.