I wasn't at the startup school either, but in my experience people don't want to have to scroll down just to find things. People will scroll down to follow something they've already started, such as a comment thread, an essay, or a list of topics. They also will scroll down to read a list of blog entries, preferably in chronological order. (Otherwise they'll prefer to follow links to particular articles)
But if there is a variety of different types of content on the page, there should at least be a table of contents to do the scrolling for you.
I wasn't at the most recent Startup School, but in general, people don't mind scrolling down; scrolling horizontally is a headache.