Check out this mini-interview. Valve’s vice president of marketing, Doug Lombardi, fills in Doug Kuchera of Ars Technica on the ins and outs of keeping it fresh with their customers. In a word…UPDATES: “The updates cause an incredible spike in sales. And when the update is offered in concert with new Achievements, new media, such as a new ‘Meet the…’ movie, and a promotion, such as a Free Weekend and/or limited-time price drop, the spike …