Microfinance in the U.S. - Does it work?

Here's a link to an excellent article in Time magazine about microfinance in the U.S. The article is a little old, but I find it very interesting.  I would assume that microfinance would be successful only in "third-world" countries.  This article, however, states that these loans have a repayment rate of 99 percent in the U.S. What makes microfinance a successful lending instrument in both "poor" and "wealthy" countries?

http://www.time.com/time/magazine/article/0,9171,1950949,00.html