[reduce]

About 35 million USD in trades on the public bitcoin-paired markets today. About 40 million USD today in total volume for all pairs on these exchanges.

http://www.cryptocoincharts.info/coins/info

[hft_throwaway]

More than when I last looked, but to put that in perspective, you could trade $40mm in a few price ticks in major currency pairs and CME avg daily turnover alone is > $100bn: http://cmegroup.mediaroom.com/2013-06-07-CME-Group-Sees-Reco...

Public spot FX markets and OTC trading do huge volumes too.

Some BTC exchanges charge like 60 bps per trade. Finding a signal to overcome that cost and do enough trading to make it worthwhile would be quite difficult.