Client-based link tracking for affiliates means that when a website visitor clicks on a link that takes them to a landing page, the Affiliate ID is saved on their browser in the form of a text file known as a cookie. The advertiser determines the cookie lifespan length; some cookies are automatically destroyed when a user closes the browser or after a period of inactivity, whereas others expire after 30 or 60 days, for example. When a customer performs the requested action on the merchant's page, a little piece of code known as a "conversion pixel" loads and reads the cookie information (transaction ID), the data is then delivered to the system for conversion tracking, and the conversion is recorded for the appropriate affiliate. Finally, the affiliate receives an affiliate commission. It is important to note that a browser cookie can only be monitored inside the same browser, so it will not be tracked if a consumer opens a new browser and completes a conversion. Free link tracking software can be either paid for (and integrated into the website) or free.