One of the four schemes I have investigated and researched how to earn extra income in the internet is through affiliate marketing programs. Affiliate programs are an automated marketing program where a merchant or web advertiser recruits online users to place the merchant’s product banner ads or buttons on their own web site to attract customers to the merchant’s web site. Online users will receive a referral fee or commission from sales when the customer has clicked the affiliate link to get to the merchant’s web site to perform the desired action. The most common types of affiliate programs include pay-per-lead, pay-per-sale and pay-per-click. Affiliate programs are also categorized. There are so many affiliate programs you can choose to earn extra income online. Click here to see a sample website.