theprof00 on 31 December 2009
I also found this explanation:
"
Taking a historic point of view, the first conclusion I draw is that it is a timed reference to an era of magazine reviews. Typical standard for a review used to be a 3-man review, using former EGM as an loose example (they used 4 for a while). If a game received perfect or near perfect scores from all reviewers, could it be said it was a triple A title? Possibly, and for the time it would make sense. Though, carrying the term into modern times, where 3-man reviews are a rarity, it looses it's context and meaning. Does that mean "triple A" is a relic of the past and that doesn't know when to die? Possibly."
from this site with other possibilities:
http://www.psu.com/forums/blog.php?b=671
