As typesetters have known literally for centuries and human-factors folks have confirmed since, there is a number of characters per line that is optimal for reading. Shorter than that, and you're going back to the beginning of the next line too often. Longer than that, and going back is too hard. Either one disrupts concentration, even if we're only talking about tiny fractions of a second.<p>Is 80 columns exactly right? Probably not. From what I've read, the ideal is probably a bit shorter. In any case, having a standard that's in the right ballpark is a good thing. There will always be some complainers, but 80 columns seems <i>pretty good</i> for <i>most people</i>. It's nothing to do with punch cards, except that their design was probably influenced by the same ergonomic principles.