"I know of a few people who did well in advertising" I do too, but those guys I know they invested in hiring stuff to do the hard work and the websites became in fact "factories" daily expanding/producing and still go strong, in other words, another way to invest your revenues is to expand your work. I know a guy that he started in the early days with one website (travel/tourism) the guy never used adsense or affiliates instead he hired mainly sales personal and he harvested a whole country! by advertising tourist businesses in main holiday destinations and doing websites for the thousands of his clients. Today he still go strong, plus, never was touched by any floridas, brandies, cafeines, pandas or penguins. His formula was every targeted destination had over 1000 pages covering every possible keyword related with the destination plus supporting each destination with individual domains linking back to the mother website.