I found this interesting quote from The Times article: https://web.archive.org/web/20100106010617/http://www.timesonline.co.uk/tol/news/world/us_and_americas/article6350303.ece

Stacy Palmer, editor of the Chronicle of Philanthropy, said the summit was unprecedented. “We only learnt about it afterwards, by accident. Normally these people are happy to talk good causes, but this is different – maybe because they don’t want to be seen as a global cabal,” he said.

Actually, the secrecy makes it seem more like a cabal.