Affiliate marketing is also called "performance marketing", in reference to how sales employees are typically being compensated. Such employees are typically paid a commission for each sale they close, and sometimes are paid performance incentives for exceeding objectives. Affiliates are not employed by the advertiser whose products or services they promote, but the compensation models applied to affiliate marketing are very similar to the ones used for people in the advertisers' internal sales department.
In 2008 the state of New York passed a law asserting sales tax jurisdiction over Amazon.com sales to New York residents. New York was aware of Amazon affiliates operating within the state. In Quill Corp. v. North Dakota, the US Supreme Court ruled that the presence of independent sales representatives may allow a state to require sales tax collections. New York determined that affiliates are such independent sales representatives. The New York law became known as "Amazon's law" and was quickly emulated by other states. While that was the first time states successfully addressed the internet tax gap, since 2018 states have been free to assert sales tax jurisdiction over sales to their residents regardless of the presence of retailer affiliates.
Spam is the biggest threat to organic search engines, whose goal is to provide quality search results for keywords or phrases entered by their users. Google's PageRank algorithm update ("BigDaddy") in February 2006—the final stage of Google's major update ("Jagger") that began in mid-summer 2005—specifically targeted spamdexing with great success. This update thus enabled Google to remove a large amount of mostly computer-generated duplicate content from its index.