Since the project is hosted at Sourceforge ( it was uploaded at Nov 2007, which means more or less a year) more than 100.000 people have downloaded simutrans executable from all releases. I think the tracker does not distinguish unique dowloads but It doesn't matter. We get more downloads each month, as you can see in the graph (http://sourceforge.net/project/stats/detail.php?group_id=196471&ugn=simutrans&type=prdownload&mode=alltime&package_id=232197).
IMHO, It means we're in the good way to create an excellent game so congratulations to everbody that have contributed or played with it!! Keep on working and playing, guys... 8)
Congratz! ;D
*fireworks*
EDIT:
I suppose we will have got ~20,000 downloads in November (considering we have got 1,000 downloads in these two days).