A year ago, Facebook launched its birthday fundraiser feature through which users can celebrate their big day by raising money for a good cause. And it appears to be a pretty popular tool. CEO Mark Zuckerberg said in a Facebook post yesterday that so far, Facebook users have raised over $300 million for over 750,000 nonprofits -- which include food banks, animal shelters and Alzheimer's research -- with the birthday fundraiser feature. "Thanks to everyone who has dedicated their birthday and to everyone who donated," Zuckerberg said.