MarketingProfs: Web Measurement: What You Don’t Know Would Make a Great Book
Steve Jackson wrote a piece on the importance of understanding exactly what users are doing once they hit a marketer's site. Ultimately, a real knowledge of how people are interacting with content and options is absolutely necessary to practice the liberal art of improving the conversion rate.
It's an interactive process, and despite the penchant for agency folks to claim that their "ad gut" tells them whether something will work or not, they're actually full of it, and they don't know until they test it.
