Additionally, she had to be less visible because her primary contribution was marketing. She describes in detail how much time and effort was necessary to create advance buzz around the game (seeding stories to the press, the "game of the year" posturing before they actually had a game).

Her contributions were major to be sure, and I don't mean to downplay her efforts towards Valve's success. But by necessity, the machinery of marketing needs to be mostly invisible, because the manipulation doesn't work when people are conscious that they're being manipulated.