Why is a raven like a writing desk?

Cecil's Columns/Staff Reports
1

http://www.straightdope.com/classics/a5_266.html

In a '70s Richie Rich comic, Cadbury (the butler), trying to be funny, said: “Why is a raven like a writing desk? Because neither one can drive an automobile!” Of course, nobody else got it (not that there was anything to get).

2

The column (including Slug Signorino’s illustration) can also be found on pages 266-268 of Cecil Adams’ book “Triumph of the Straight Dope”.