Down at the bottom of the page it says “Contents of the Straight Dope Message Board and the Straight Dope Web site are copyright 1984-2000 by the Chicago Reader, Inc.” That should probably be updated to say “copyright 1984-2001”.
The Straight Dope Homepage ( http://www.straightdope.com ) has “Copyright © 1996, 1997, 1998, 1999, 2000, 2001 Chicago Reader, Inc.” Seems strange they don’t include 1984-1995, especially since so many Straight Dope Classics date from that period. The first Straight Dope book came out in 1984 but some of the columns must have been published in the pages of the Chicago Reader and other periodicals in earlier years.
And another thing: There is one column available online that dates from well before 1984 that isn’t in any of the books: The first Straight Dope column 02-Feb-1973, which I am quite sure is still copyrighted.