It's more or less make up as I go along, but the original plot was that it was going to be about a fan of C64 computers then I gave up on that really quick. Thought that it'd be much easier to be about the computer itself and the owner of that computer (who else?)
I got started on it because the TRON dvd made me think about old computers and how much I missed my own Commodore 64. So, I pretty much made the comic to show what would have happened if I still had mine... but that quickly got crazier when I somehow included the C64 robot/soul of the computer. ^^;
The basis: there were secret weapons... that there were robots created to work with certain computers for the sole purpose of education. Vic 20, C64, and C16 are the robot models that all look alike but their hair colors are different (to reflect the computer case colors.) (Vic 20, C64, and C16 all had the exact same cases, only they were differently colored. Vic 20 was white, C64 was light brown and C16 was black.)
Apple and Microsoft were simply different kinds of model. Apple being typically "advanced" looking and Microsoft being... well, microsoft.

(Hence the computer viruses chasing after MS in one of the comics.)
I've been working on a manga script for the webcomic that I'll eventually draw and post as a special. It will detail the time spent with my computer and C64's thoughts and a solid explaination of why she can actually interact with people in the comic strip. (I never quite brought up the robot concept in the current comic because I was afraid that people would accuse me of ripping off MT or CLAMP. The living robot concept is too popular.)