Here's a counter point, though. For readability, you should make your text blocks around 33em wide, which is about 66 characters. If you lose the side bar, you have to choose between really long lines, which suck, or multiple columns which is a chore at best, and impossible at worst since columns only really work in the format of a "page," since the reader would potentially have to scroll down then scroll back up for the next column.

So my caveat is that if you lose the side bar, don't allow your text to expand willy nilly!