Pynchon Bumper sticker

[John Pendergast]

I am assuming this is old news to everyone on this list but me, but 
yesterday I saw a bumper sticker, "My other car is a Pynchon novel", in my 
local Target parking garage. I did a search and found this:
http://www.boingboing.net/2005/05/06/bumper_sticker_my_ot.html

How long have these been around, and why don't I have one? And what the hell 
does it mean?

John Pendergast