Affiliates receive credit for a conversion by placing a cookie on the computer of visitors they send to a merchant site, allowing the network to attribute sales to specific partners. Many merchants will give credit for a sale to an affiliate even if the sale comes after the initial visit to the site. For example, assume:
- Visitor clicks affiliate link on publisher site;
- Visitor browses merchant site, but doesn’t buy anything;
- Visitor returns to merchant site (by typing in URL) a week later and completes purchase.
Many merchants will still give credit for this sale to the affiliate, even though the visitor came directly to the site and not through an affiliate link when they completed their purchase. This is a fair solution in many cases, since many customers take time to make a decision and commit to a purchase. In the scenario above, the affiliate still provided a valuable service to the merchant–getting the customer to their site–and deserves to be compensated for that.
A 30-day cookie is the standard, but there can be quite a bit of variation here. Some cookies expire after just a week, while others run indefinitely. From an affiliate perspective, the longer the cookie length the better.