In our analysis of Rand’s effective face-to-face presentation we noticed that he needed at least five minutes to make the case for SEOmoz PRO. Yet the existing web page was more like a one-minute summary. Once we added the key elements of Rand’s presentation, the page became much longer:

It’s interesting to note that Amazon.com, which is known for its relentless testing, tends to have extremely long product pages. Just see the page for its Kindle reader.

via conversion-rate-experts.com

There’s a lot of useful information in this article, but this page length comparison and the technique of writing copy with ‘curiosity rather than overt “buy me” language’ were the big takeaways for me.