Who's done more to lift people out of poverty? - Microfinance or WalMart

Greg Mankiw appproves of John Tierney's message. Tierney:

I don't want to begrudge the Nobel Peace Prize won last week by the Grameen Bank and its founder, Muhammad Yunus. They deserve it. The Grameen Bank has done more than the World Bank to help the poor, and Yunus has done more than Jimmy Carter or Bono or any philanthropist.

But has he done more good than someone who never got the prize: Sam Walton? Has any organization in the world lifted more people out of poverty than Wal-Mart?

The Grameen Bank is both an inspiration and a lesson in limits.
. . .
there's a limit to how much money villagers can make selling eggs to one another -- a thatched ceiling, as Michael Strong calls it. Strong, the head of Flow, a nonprofit group promoting entrepreneurship abroad, is a fan of the Grameen Bank, but he figures that villagers can lift themselves out of poverty much faster by getting a job in a factory.

The best way for third world villagers to tap ''the vast pipeline of wealth from the developed world,'' he argued in a recent TCSDaily.com article, is to sell their products to the world's largest retailer, Wal-Mart. Strong challenged anyone to name an organization that is doing more to alleviate third world poverty than Wal-Mart.

So far he's gotten a lot of angry responses from Wal-Mart's critics, but nobody has come up with a convincing nomination for a more effective antipoverty organization.

UPDATE: More at Cafe Hayek.