On Tue, 18 Nov 1997, SCHLUETES@lucas.lbe.edu.on.ca (Emperor Stephen "The Mega Man" Schlueter) wrote:

I decided to change the topic of my rambling mind because apparently 
nothing can ever be as controversial as how someone name is spelled. 
Note To Those Who Wrote: I made it quite clear yesterday that I 
should've kept my mouth shut on the whole spelling thing because no one 
has held back in pointing out that I know nothing about this. OKAY! I 
ADMIT IT! I DID A REALLY STUPID THING!! STOP ATTACKING ME!! I GET THE 
POINT!! I don't care about Ryougas or Tendous or Kunous or Ukyous 
anymore (but I'm still not accepting Ukkyo, the SNES spelling, as a 
correct form of the name Ukyo, or Ukyou or whatever.) 
My question here today is: Why are they called Lemons? Why would someone
refer to a twisted sexual fanfic as a lemon? Outside of the fruit the 
term 'Lemon' is only used to describe something defective (I'm sure the 
spelling people are going to tell me I'm defective now or something.) So
why do we call them lemons? 

	Basically it's because the first people posting them called them Lemon Fanficts and the name 
has become established.  As to why they did, it was probably a refference to the Cream Lemon OAV 
series, one of the first Anime series of the Genre (And the series responsible for Project A-ko)