I attended Tufte’s course in Washington D.C. last year. I found it to be an excellent course in presentating information and overview of his printed material. It was a truly enlightening experience for me, a web developer.
He specifically addressed digital displays and their inability to match print in terms of resolution. He asserted that digital displays are a long way off from matching print resolution. However, he noted that digital displays typically allow for interaction. He suggested providing summary data that can be summarized and then drilled into or zoomed into in order to reveal more precision. Also, he suggested that non-web interfaces (mission control, etc.) require multiple display units (see http://research.microsoft.com/displayArticle.aspx?id=433 ). The best of both world’s would be interactive digital display with print-like resolution or print with interaction, but until those options exist, we need to make design decisions appropriately.
A lot of people like to bash Tufte without reading his material or attending his courses. They don’t realize that the majority of the examples he cites are printed and span the course of history. It’s critical to really understand his material before critiquing it.