What Affiliate marketing is

A revenue sharing arrangement between online advertisers or e-commerce merchants and online publishers or Web site owners, whereby payment is based on performance measures, such as the number of sales, clicks, or registrations that the affiliate refers. In other words, two companies agree to link to one another; if someone clicks from site A to buy something at site B, site A gets a commission on the sale. Affiliate software provides the tracking and reporting of commission-based activities (the sales, clicks, or registrations). Amazon.com pioneered affiliate marketing by getting as many other Web sites as possible to join its affiliate network and sell its products, thereby greatly extending its marketing reach.

The meaning of Legacy business

Slang for a traditional brick-and-mortar firm. Accurate or not, anything characterized as "legacy" is perceived to be old or outdated (as opposed to a new economy company, for example).