Mad magazine (a humor magazine) made fun of magazines when it published the following joke in 1960:
 
“Magazine . . . bunch of printed pages that tell you what’s coming next issue.”
 
The joke was mostly forgotten until the 1990s, when it appeared with other humorous definitions on Usenet groups such as rec.humor and alt.humor.
 
     
Google Books
A Golden Trashery of Mad;
The latest collection of humor, satire, art, and fun for all from Mad magazine
New York, NY: Crown Publishers
1960
Pg. 81:
“Magazine . . . bunch of printed pages that tell you what’s coming next issue.”
 
Google Groups: rec.humor 
Jeffrey David Brown
5/15/91
(...)
MAGAZINE—bunch of printed pages that tell you what’s coming in the next issue.
   
Google Groups: rec.humor
Henry CateIII
10/24/94
(...)
MAGAZINE—bunch of printed pages that tell you what’s coming in the next issue.
   
Google Groups: rec.humor
Nancy Carson
5/6/97
(...)
MAGAZINE….......bunch of printed pages that tell you what’s coming in the next issue.
   
Google Groups: alt.humor
Keith E. Sullivan
5/22/97
(...)
MAGAZINE—bunch of printed pages that tell you what’s coming in the next issue.
   
Underdeprived Humor
December 27, 2008
Daffynitions
(...)
MAGAZINE: bunch of printed pages that tell you what’s coming in the next issue.
 
you got to be kidding’s blog
Terms Everyone Should Know
~ by yougottobekidding on April 9, 2010.
(...)
MAGAZINE
A bunch of printed pages that tell you what’s coming in the next issue.