Except for being butt-ugly, I've been enjoying my love-affair with Kiva for quite some time now, because I absolutely love helping other entrepreneurs in whatever way I can. I've now made 26 loans on Kiva already, totaling a tad over $1000 and I'm constantly amazed at how easy they pull me to further grow that portfolio of mine.
Basically what happens every couple of weeks is that I get an e-mail saying that $x.x worth of loans had been repaid and that this credits were now available on my Kiva account. So I log into Kiva immediately and reinvest the money in new loans. But something else always happens: I invariably end up adding another $50 or $100 to the portfolio (in addition to redistributing the available credits).
I just think that this is such a great marketing strategy on their part, plus it's not rocket science or groundbreaking either. They're really just tapping into my own "need" to be involved in social good in one way or another.