What we’re going to look at is one category here, e-business and e-marketing. When you click on that category, Clickbank automatically sorts the results by popularity. Popularity is basically how many sales that product is getting. As an affiliate, you definitely want to sort the results by gravity. Click on this little dropdown menu and choose Gravity. Gravity is complicated, but it’s basically how many different affiliates are making sales from that product. That’s important for you as an affiliate, because the more different people are making money from that product, that really shows that it’s a proven winner.
The seller, whether a solo entrepreneur or large enterprise, is a vendor, merchant, product creator, or retailer with a product to market. The product can be a physical object, like household goods, or a service, like makeup tutorials. Also known as the brand, the seller does not need to be actively involved in the marketing, but they may also be the advertiser and profit from the revenue sharing associated with affiliate marketing.

2nd tier.  If you are an affiliate for a particular program and you refer others to sign up for that affiliate program, a 2nd tier program will pay you when the affiliates you referred make sales. For example, I am an affiliate for Ultimate Bundles. If you join their affiliate program via my 2nd tier affiliate link here. I will get a small percentage of any sales you make going forward.
When promoting affiliate offers, just make sure you are fully aware of all the terms and conditions attached to your affiliate program. Some programs can be strict about how they allow you to promote their products. For example, some may limit you to banner ads and links only, while others will allow you to use paid advertising, but won't allow email marketing. 
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