Kara Swisher's camera briefly caught departing Yahoo executive Qi Lu Tuesday night smiling next to a laughing David Sze, the Greylock Partners venture capitalist who loves to talk up his seat as a board observer at Facebook. But she now admits she didn't recognize him at the time. What's the significance of Lu sitting down with Sze? Lu might be up for a job as an entrepreneur-in-residence at Greylock, or with one of Sze's portfolio companies. "I may do it again," Sze joked with Swisher, about hiring Lu's colleague as an entrepreneur-in-residence. Was that why Lu was smiling?