Facebook's vice president of product management, is reportedly leaving the company to join Benchmark Capital. Two possible interpretations leap to mind: Sheryl Sandberg, the Facebook COO recently hired away from Google, is pushing out, one by one, the executives closest to Zuckerberg, leaving him increasingly isolated. Or Zuckerberg, loathe to give up control over Facebook as a product, is doing it himself. Update: Cohler is joining the VC firm as a general partner, not an entrepreneur-in-residence, as we'd first reported — a considerably more prestigious role, where he'll be investing money in startups himself, rather than waiting to get funded. He'll stay tied to Facebook a "special advisor" to Zuckerberg — which suggests that any falling-out was not with the Facebook CEO. Cohler, for his part, tells Swisher he got along well with Sandberg, and helped recruit her to the firm.