How many people are trading bitcoins?

[JorgeStolfi]

Is is possible to estimate how many distinct people are actually trading bitcoins in a given day (or week, or month)?

[empoweoqwj]

Not really.

If you had access to account records at the major exchanges (bitstamp, mtgox, btce, bitfinex, campbx, kraken etc), you could make a guestimate, but so many transactions go on outside these major exchanges (hand to hand transaction, other exchanges etc), it would only be a guestimate at best.