Since I’m running Deer Park, I thought I’d see what CSS3 columns actually look like. Being too lazy to type a few lines into a text file, I googled and found this: Well, I’m Back: Gecko 1.8 For Web Developers: Columns. Lo and behold, that very blog entry uses two columns.
Multiple columns are nice, because you can use the full width of your media without your lines being obnoxiously long and painful to read. However, for reading on the screen I think I’d prefer to waste screen real estate and keep scrolling down vertically. It’s rather annoying to hit the end of the column and then have to scroll back up to the top to continue.
For printing, however, having multiple columns is great. For your eye to jump from the bottom of one column to the top of the next on the same page is very quick and painless.
Sure, when viewing on screen, you can get back to the top just by hitting the home key. But, on screen there is no vertical limit. Why interrupt the flow of reading for no appreciable gain?