[nwh]

I don't think we are anywhere near the blocks being half full, lots are less than 100kB except for Eligius. Is there anywhere displaying this metric?

[gnaritas]

I wasn't trying to put a hard number on it; I said about half because that's the number I keep hearing repeated when discussions occur.

https://blockchain.info/charts/n-transactions-per-block

Lots of other interesting charts there. In any case, it doesn't really matter as to the main point that exchanges don't do on block trading, the volume would be far too great for what the network can handle.