This image provided by KTVU-TV shows search efforts revealing part of a plane Wednesday April 30, 2014 in the San Francisco Bay in San Francisco. Searchers on Monday located the Cessna under 13 feet of water about 1 1/2 miles off the Richmond shoreline east of San Francisco. (AP Photo/KTVU)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)
Facebook CEO Mark Zuckerberg gestures while delivering the keynote address at the f8 Facebook Developer Conference Wednesday, April 30, 2014, in San Francisco. (AP Photo/Ben Margot)