What does Camille Hart know about Facebook COO Sheryl Sandberg's plans that we don't? Hart, Sandberg's longtime executive assistant who followed her from Google to Facebook, has left the company after less than a year, we've learned, confirming a note left by commenter insidefb. We can't wait to hear Sandberg's spin on this departure. Remember her now-classic line about the series of executives leaving Facebook this summer? "There is no specific underlying story behind the few execs leaving our company,"As much fun as Hart seemed to be having at Facebook, there's a long list of reasonable reasons for Hart to leave: She already made money by joining Google before its IPO. She's shortening her commute by taking a job with the San Francisco Giants. She doesn't want to keep working from 7 a.m. to 7 p.m. But I am skeptical. Why not stay a year and vest a first round of stock options? I can't help wondering if the timing of Hart has something to do with the election — and the opportunities a Democratic administration has opened up for former D.C. power player Sandberg to return to Washington.