"There's a lot to be said for doing something well and carving out a reputation as an authority in your niche. For one thing, you'll have an opportunity to 'monetize' your content in a variety of ways--not just from AdSense. And if your content is 'evergreen,' your revenue base will grow (thereby increasing your income) month after month, year after year.
In a nutshell: There's a lot more to publishing than the Web equivalent of those weekly throwaway ad supplements that arrive on your doorstep or in your mailbox." europeforvisitors