The pictures and diagrams in the article certainly help with the understanding of crop factor, but I'm going to get picky here, and point out this incorrect statement - "The total physical area of the 35mm film is 66.6% larger than the physical area of the CCD. This equals a factor of 1.5"
The area of a 35mm neg, at 24x36mm is 864 sq mm, while a D70 sensor at 15.7x23.7 (near enough to 16x24) is about 370 sq mm. This equals a factor of about 2.33.
It's the linear dimension which is the one used for determining crop factor, not the area. The crop factor is near enough to 1.5, exactly it is 36/23.7=1.52. (Or if you use the other dimension, 24/15.7=1.53) The aspect ratio of the two formats is not identical, which accounts for this slight difference.
Apologies if I'm being overly picky here, I've been reviewing a lot of documents this week at work, perhaps I haven't wound down yet...
Cheers