Affiliate marketing is a popular way of promoting an online business in which an affiliate is rewarded for visitors or subscribers. In other words, it is a modern variation of the practice of paying finder’s fees for introducing a new client. Reimbursement is done through certain value for each visit, which may be pay per click, pay per lead, or pay per sale, or a combination of any of these three.

There are some e-commerce sites who run their own affiliate programs and others who utilize third party services provided by intermediaries to track traffic or sales that are referred from affiliate sites. Today, affiliate marketing contributes to around 15-20% of online revenue growth.

A number of advertisers offer multi-tier affiliate marketing programs that distribute commission into a hierarchical referral network including sign-ups and sub-affiliates. In other words company X signs up an affiliate program with an advertiser and gets rewarded for an increased activity in his site. Now if company Y and Z, attracted by A’s increasing profits sign up for the same program using the same sign up code that of A’s then all future activities will result in lower commission for A too.

There is much debate around the practice of affiliate marketing as spamindexing is a constant practice used by unethical users. Spam is the biggest threat to organic search engines who aim at providing quality search results for keywords or key phrases entered by users. Search engine giant Google has come up with an Algorithm, which is specially targeted at spamindexing and removing a large amount of spasm.