What does it do? As Claire Cain Miller put it in the BITS blog:
"Unlike tools currently on the market for foundations to use internally, Acumen’s tool will allow foundations to see data from other grant makers. That will help them assess how a potential grantee shapes up and compare nonprofit performance across business models or sectors, like health investments in Africa or inner-city education in the United States. PricewaterhouseCoopers is developing the data aggregation system, which is scheduled to be live in 18 months."
The platform was unveiled at the Clinton Global Initiative. Details are here, press coverage in BusinessWeek is here, Bits Blog post is here.