RE: house "ANON"
To add:
Retail Houses do not have the option to mask their trade under anon, such as Penson, TD, RBC, Scotia, BMO.
There are others that also may not - such as Questrade, which i suspect d not have based on all the trades i've seen, but have not confirmed.
Canaccord does have anon option - i can guarantee you that.
So the point of monitoring anon is - 99.9% of the time it's larger sophisticated traders - they may not be the same entity, but an experienced trader can pick out the daily trading personalities, and there be a few anons trading, and yes, occasionally i'm sure they're wrong ;)
So i sure wouldn't discount that statistic either.