Mechanical Turk is Amazon's take on micro-jobs. These are small miniscule-jobs that you can do for other people, which they call HITs, or Human Intelligence Tasks. These are super simple tasks that anyone can do. Some examples are listing off some URLs with certain kinds of images for one cent, or recording a few phrases with a microphone for 6 cents.
If you have an e-book or online course that you'd like to promote, ClickBank makes that easy. Once you sign up as a vendor you can list your product with them and set the commission percentage you are willing to pay to anyone who chooses to market and promote your product for you. Once your product is listed, other ClickBank users will start promoting it on their own websites. This will drive traffic to the sales page on your website and hopefully result in sales.
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).