Here's an example of the effect it creates: https://www.youtube.com/watch?v=8GfKBvs53Ss
When users click through and buy something, you'd get a percentage of the sale. It could also be a lot more beneficial to users than just showing banner ads.
If you combine it with actually providing a benefit (i.e. a diamond block linking to the wiki page on diamond blocks), your users might very much appreciate the functionality.