Affilate - Someone who promotes a merchant's products in exchange for a commission.
Click-Through - When a user clicks on a particular link.
Commission - Compensation paid to an affiliate for participating in a merchant's affiliate program, usually a percentage of each sale generated from a link on that affiliate's site. Commissions may also be a flat fee for each purchase or action.
Conversion Rate - Percentage of visitors who make a purchase.
Impression - When a link is displayed to a user.
Keyword - A word or phrase put into a search engine to find a web page on that topic. Putting these words and phrases into a web page help the search engines find them.
Merchant - Someone who sells products or services on the internet.
Return Days - The number of days between a user's first visit to a merchant's website and their next visit.