Hacker News Reader

> published widely distributed statistics of how much aggregate margin was outstanding on a day to day basis.

Do you have a link? I didn't find those stats after a cursory look at the Bitfinex and BTCE sites.

I don't know about BTC-e, but the swaps information from Bitfinex is usually available at bfxdata.com

Thanks. I am not sure if this also captures their margin trading.