A browser extension is a plug-in that extends the functionality of a web browser. Some extensions are authored using web technologies such as HTML, JavaScript, and CSS. Most modern web browsers have a whole slew of third-party extensions available for download. In recent years, there has been a constant rise in the number of malicious browser extensions flooding the web. Malicious browser extensions will often appear to be legitimate as they seem to originate from vendor websites and come with glowing customer reviews.[28] In the case of affiliate marketing, these malicious extensions are often used to redirect a user’s browser to send fake clicks to websites that are supposedly part of legitimate affiliate marketing programs. Typically, users are completely unaware this is happening other than their browser performance slowing down. Websites end up paying for fake traffic number, and users are unwitting participants in these ad schemes.

Although it differs from spyware, adware often uses the same methods and technologies. Merchants initially were uninformed about adware, what impact it had, and how it could damage their brands. Affiliate marketers became aware of the issue much more quickly, especially because they noticed that adware often overwrites tracking cookies, thus resulting in a decline of commissions. Affiliates not employing adware felt that it was stealing commission from them. Adware often has no valuable purpose and rarely provides any useful content to the user, who is typically unaware that such software is installed on his/her computer.
If my piece of content is so unique and valuable around hiking backpack recommendations, that other reputable outdoor websites are willing to link to it and build the page’s authority, then I’d have a very real opportunity to rank high in organic search for these search terms (meaning, my page will come up first when someone searches for hiking backpacks).