A term used by those 2 out of 3 lol cats that believe in Ceiling Cat and do not believe in Christianity's "God", therefore they do not use the term "OMG" a.k.a "Oh My God".
"OMCCWTFBBQ! A Capshun!" said the lol cat on icanhascheezburger.com
When you are laughing a shit load and you're typing at the same time, you get typos. Omcputer is a result of that. It means computer, just typo'd.
xGoDLyNooBx: LOL
xGoDLyNooBx: OMFG
CLTCOMMANDERSSSD: lol
xGoDLyNooBx: apple jacks is apple hax, apple being the apple omcputers
CLTCOMMANDERSSSD: omcputers?!?!
CLTCOMMANDERSSSD: LOL