It's not scientific but my estimate would be that there are something like 500,000 less users on at anyone time.
I can remember around summer this year we had highs of 3.8 million online. On average the most I see now is 3.2ish. Still a lot of folks admittedly but it is a worrying trend.
At this minute there appear to be 2.3 million online - previously that would have been approaching 3 million. I mean for a Saturday morning.
If this keeps up I can see it shrinking to nothing. Have to admit ive been trying out torrent proggies (very reliable)- winmx - and soulseek. Suspect many others are looking for alternative methods too.