GiveWell? Aren't those the guys that astroturfed MetaFilter a few years ago?
Their apology (not half bad): http://www.givewell.org/about/shortcomings
Deceit in lending is not uncommon among microfinance organizations, but it's surprising to see it from a YC-backed company. I look forward to Zidisha's response, I'm sure they'll shed more light on it.
MeFi's analysis, which FWIW, notes that most of the offending activity was done under the founders' real first-names: http://mefiwiki.com/wiki/Givewell
(Where is AirBnB's apology for violating Craigslist's TOS with the spamming from "Jessica"?)