The US's No. 3 social-network site, MyYearbook.com (see this), just launched a new feature called "Causes," YPulse.com reports. "MyYearbook users can choose from a number of causes like ending world hunger, fighting climate change, saving the rainforests or curing cancer. They donate with virtual money, i.e. $40 buys one grain of rice (expensive grain!), and then get a badge on their profile … [Read more...] about MyYearbook helps teens give to ‘Causes’