Does the SDope staff really mine the General Questions message board for these questions, or is it just recycled questions (and answers) from his books? - Jinx
Questions occasionally come from the boards, but not often. When it does happen, it’s usually an addendum to a previous column, resulting from a “Comments on Cecil’s Columns” thread.
And there’s one new question by Cecil each week (it shows up on Friday, and gets its illustration on the front page). All other columns by Cecil posted on the front page are repeats.
Neither in my relatively short experience. All the questions I’ve seen were mailed in to Cecil.
I’m a little confused by exactly what you’re asking, Jinx, so I’ll over-answer.
There’s a variety of different types of things that appear under “Today’s Question.”
On Monday and Wednesday, the question is usually one that Cecil had answered long ago, and is in the Archives or the Books. Cecil’s been doing this for around 30 years, so there’s a wealth of old questions that are still interesting.
On Tuesday, the question is usually a Staff Report, written by a member of the Straight Dope Science Advisory Board (SDSAB) or by an occasional Guest Contributor. These questions are almost always taken from mail to Cecil, things the Teeming M’s would find of interest, but that Cecil Himself doesn’t want to tackle. For instance, because the answer would be too long for a column, or because the answer is readily found elsewhere for someone who goes looking. (Staff Reports occasionally synthesize material from several sources, for instance.)
On Thursday, the question is either a Staff Report or one of Cecil’s old columns. It sort of depends on how much work Ed Zotti has to do that week – it’s obviously easier to recycle an old column.
On Friday, there’s a new column by Cecil. Cecil sometimes (although not often) takes questions from the Message Boards, but usally from his email or reg’lar mail.
That help?
In regard to the reply above…sounds like Cecil is competing with the theme days of the Mickey Mouse Club! 
- Jinx