Facebook CEO Mark Zuckerberg rings the Nasdaq opening bell from his corporations headquarters in Menlo Park, California (May 18) Subscribe to the Associated Press: bit.ly/APYouTube Download AP Mobile: www.ap.org/mobile/ Associated Press on Facebook: apne.ws/c7lQTV Associated Press on Twitter: apne.ws/bTquhb Associated Press on Google+: bit.ly/zuTKBL