You also don't have much say in how much you're able to make with these revenue streams. Products (e.g. ebooks, video courses, apps, etc…), on the other hand, are your own. You can price them at whatever you want them to be or at least what your audience is willing to pay. This gives you the freedom to create whatever type of content you want and earn however much money you want.
Perhaps the most popular network for placing these types of ads is Google AdSense. With this program, you do not need to be in direct contact with advertisers; you simply place the banner on your site, Google chooses ads relevant to your content, and your viewers click on the ads. There are countless similar programs available if you find that AdSense doesn’t work for you, such as Chitika, Infolinks, and Media.net.