In most cases, site monetization via Adsense isn’t the best way to go. Generally speaking, you can secure a higher return on investment by creating a quality site featuring affiliate links to products that sell for substantially more than what you’ll net per Adsense click.
True, the conversion rate will be lower, but the considerably higher value of each conversion can more than make up the difference.
That being said, there are times when Adsense does make sense. Sites designed to attract search engine traffic that are thick with content but short on quality, for instance, might fit that bill. Although Adsense officially opposes these made for Adsense (MFA) sites, they can be a workable means of generating income.
Another example is a site that will serve up ads offering high per click values. A site that features ads paying a nickel may be better suited for affiliate sales, but if you can isolate keywords generating a dollar per click, the math rapidly changes.
The problem with chasing expensive Adsense clicks is competition. Adsense-based Internet marketing models exploded in popularity a few years ago and those who are now entering the field may find themselves up against some tough competition, especially in the more lucrative niches.