For a few hours every week, you can use the growing power of the Internet to get informed, find others with the same interests, see the barriers, and find ways to cut through them.

Don't let complexity stop you. Be activists. Take on the big inequities. It will be one of the great experiences of your lives.

You graduates are coming of age in an amazing time. As you leave Harvard, you have technology that members of my class never had. You have awareness of global inequity, which we did not have. And with that awareness, you likely also have an informed conscience that will torment you if you abandon these people whose lives you could change with very small effort. You have more than we had; you must start sooner, and carry on longer.

Knowing what you know, how could you not?

And I hope you will come back here to Harvard 30 years from now and reflect on what you have done with your talent and your energy. I hope you will judge yourselves not on your professional accomplishments alone, but also on how well you have addressed the world's deepest inequities ... on how well you treated people a world away who have nothing in common with you but their humanity.

Good luck.