Sidebar, Rail or Margin?
Back in the days before CSS when sidebars started to become popular they were done with tables. It wasn’t long after CSS came out that designers figured out how to make columns with CSS and now it seems like every web page has a sidebar or two, some still done with tables.
Sidebars can be an important organizational and navigational aid for moderate to large sites with widely varied content. They’re a great place for small navigational calendars and category lists.
For smaller sites a sidebar can be an expanse of white space that begs to be filled. Many blog authors feel compelled to fill that space with all sorts of useless gadgets, ads unrelated junk. I found myself in that same position. All that space just sitting there. I felt it had to be filled with something, anything, to balance the main content.