Valve have posted the slides of Mike Booth’s recent Stanford AIIDE-09 conference presentation. While only the first section on path-finding will likely be of most interest to animators, he also goes some way to breaking down the famed AI Director used to dynamically tailor the game experience for each new playthrough.
They certainly give the outward impression at least that they’ve attained the developer holy grail of sharing technology across projects, recently announcing early Bots for Team Fortress 2 using the same decision-making as described in this paper.
Find a list of all of Valve’s speaker presentations here.