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.
Focus on reviewing products and services that fall within your niche. Then, leveraging the rapport you have created with your audience and your stance as an expert, tell your readers why they would benefit from purchasing the product or service you are promoting. Almost anything sold online can be reviewed if there is an affiliate program – you can review physical products, digital software, or even services booked online, like ride sharing or travel resort booking. It is especially effective to compare this product to others in the same category. Most importantly, make sure you are generating detailed, articulate content to improve conversions.
This relationship can take multiple forms. You may partner with a brand launching a specific product and receive a percentage of the revenue generated by your referrals. Or, if you work with websites like Amazon, you receive a percentage of whatever purchase a follower makes through your referral links, even if they don't buy the product you were specifically recommending.