The insult shitgibbon predates Twitter.
Searching Usenet, I found several examples from 2000 and 2001 from the British bootlegging scene, where people would record the audio (and sometimes video) of a gig, and then arrange trades of tapes with other bootleggers and fans.
A shitgibbon was someone who trades copies and doesn't appreciate the effort it takes to record a concert. Two of these three examples are from the same person (and possibly the third too).
2000 March 21, EvilJam32, “Re: Shall I film the Hip in London 8th June?”, in alt.music.tragically-hip:
It's clear that some of you expect others to do the hard work for you (ie
filming)then belly-ache nauseatingly when you're asked to cough-up for it! .As
for taping,I totally endorse taping trees and suchlike but franky audio-ing is
a piece of piss compared to filming and 99% of filmers will only trade with
other filmers.Why should lazy so-and-sos like you get copies of our tapes for
free? But if you really baulk at buying videos,I'll tell you what,I will film
the London show but because I don't want to be accused of bering mercenary,i'll
keep the tape to myself-no sales,no trades.Good luck and goodbye to the most
sick-making,hypocritical bunch of shitgibbons i've yet encountered on the Web!
2000 November 28, Master8 uk, “Re: MORRISSEY- "Battersea Park" 1997 VIDEO!”, in alt.music.morrissey:
[in response to an offer to sell a bootleg for $20 or trade]
get the f*ck off this newsgroup,shitgibbon!!
2001 September 26, Master8 uk, “Re: good trader: LIVIDZ”, in alt.music.bootlegs:
>But his prices are a bit high.
So they should be,when he's the feller "what" films them.If you want cheap then
feel free to buy from any one of 10,000 shitgibbons out there "who film from
their computer keyboards" (as it were) thereby saving so much $$,that they can
cut you a GREAT deal for a 4th gen mastepiece!