Effective Altruism: Where Should You Donate Your Time or Money?

The Effective Altruism movement asks people to donate more of themselves to charities, and make sure that those causes will use their resources as efficiently as possible.  Are you a less moral person for giving money to the Red Cross, if you could save more lives donating elsewhere?  Is it ok to prioritize your own family, friends or community over people living around the world who are in greater need?