Huh! 37Signals has all this other stuff that I never scrolled down to before. Interesting.
The black section at the bottom I always just assumed was a footer, not a call to action, and honestly never read that before.
Ironically it seems to me the news sites seem to have done away with the concept of the fold the best. http://www.bbc.co.uk/, http://www.nytimes.com/, http://seattletimes.com
Care to elaborate?
I'm still sticking to my guns that 37signals heavily implemented tactics for optimizing click-throughs and conversion ratios based on their bread and butter services being listed with bright and bold colors ABOVE THE FOLD.
On that note, it's slightly disheartening that this article is generating such attention on HN.
He uses a tactic of providing a teaser and little textual content above the fold in order to lead one to scroll down. The article author uses the fold in a comical sort of way with reference to the iceberg. Nice idea though.