SBoomTown reporter Kara Swisher rappelled from a skylight at Jerry Yang's secret hideout to score this draft copy of an ad, in which a bunch of tech bigwigs come out in favor of gay marriage — or at least in opposition to Proposition 8, a California state ballot initiative which would ban it. No Valley company in its right mind would be seen opposing gay marriage, so why bother?Right: Because it's an awesome branding opportunity. The draft is a self-parody of corner office drama, full of Honorary Co-Chairs, Leaders, and Former CEOs. But the real story is: Who's missing? Sergey Brin and Eric Schmidt are here, but not Larry Page. Twitter's Ev Williams is here, but not Digg's Kevin Rose. Federated Media: Present. TechCrunch: Absent. Mark Zuckerberg is not here, but Sheryl Sandberg pulled a John Hancock: She's right up top, where Owen can't miss her. Oh, look, she's trying to make nice! She's going to be sorry.