Man I remember the good old days when Gox would do almost 100,000 BTC in a 24 hour period.
Right. What happened to 100,000? Sigh. It seems rather boring now.
Gox no longer handles the vast majority of BTC exchange volume. Well - they still do more than all other exchanges combined, but not nearly what they used to do (don't hold me to the chart being accurate within a ~10% range, but it's a fair indicator).
http://bitcoincharts.com/charts/volumepie/I think a strong trend toward private selling (due to a large-enough number of factors that I don't feel like listing them) is also contributing to a lower overall volume on exchanges.
Volume - and this is probably the biggest factor - has also pretty low at this particular moment because the price has been exceptionally stable, so there isn't much volume from traders.... but we all know that could change within a few minutes at any time. The $2xx-~$60 crash took about 7 days and saw nearly 2M BTC trade on Gox alone. Since mid-May, though, it's been unusual for Gox volume to exceed 100k/day. It doesn't help that Gox hasn't processed a USD wire withdrawal since just a bit after that time...
It'll be interesting to see if BTC prices plummet on Gox once (if) they start pushing USD out again. Right now, BTC on Gox commands a 10-15% premium over other exchanges, I assume because it's much easier to move BTC on Gox than USD. Gox could make tens or hundreds of millions just by selling BTC bought on other exchanges with the USD they can't (or won't!) send out to customers....