In February 2000, Amazon announced that it had been granted a patent on components of an affiliate program. The patent application was submitted in June 1997, which predates most affiliate programs, but not PC Flowers & Gifts.com (October 1994), AutoWeb.com (October 1995), Kbkids.com/BrainPlay.com (January 1996), EPage (April 1996), and several others.
When promoting affiliate products online or within emails, it's important that you follow the guidelines from the Federal Trade Commission so that your readers and followers are well aware that they are clicking on affiliate links and you will be making money from their purchase. It's simply good business to be completely transparent about the nature of the transaction.
In November 1994, CDNow launched its BuyWeb program. CDNow had the idea that music-oriented websites could review or list albums on their pages that their visitors might be interested in purchasing. These websites could also offer a link that would take visitors directly to CDNow to purchase the albums. The idea for remote purchasing originally arose from conversations with music label Geffen Records in the fall of 1994. The management at Geffen wanted to sell its artists' CD's directly from its website but did not want to implement this capability itself. Geffen asked CDNow if it could design a program where CDNow would handle the order fulfillment. Geffen realized that CDNow could link directly from the artist on its website to Geffen's website, bypassing the CDNow home page and going directly to an artist's music page.
Google Autocomplete – go to google.com, start typing a phrase and look at the dropdown autocomplete results. You can use the underscore character “_” to have Google fill-in-the-blank. Just make sure the last character you type is an underscore. Try using plurals and change the word ordering to see different results. This is how I find 90% of my keywords.
If the answer to each of these questions is a resounding yes, rather than jumping to conclusions immediately, take time to research whether or not others are out there making a sustainable affiliate income from products and content in this niche. In a sense, competition is a good thing here—it'll help you validate your idea and prove that it's worth of building a business around.