@helsinkiharbour SourceForge used to track downloads for us: https://sourceforge.net/projects/triplea/files/stats/timeline?dates=2002-01-17+to+2017-01-01
I don't know if we have a download count on the new website or github.
I'd say there are a few hundred active multiplayer lobby players and probably a few hundred active PBF/PBEM players. To verify you can join the lobby and there is usually somewhere between 30-100 people in it. PBF/PBEM is mostly on A&A: http://www.axisandallies.org/forums/index.php?board=40.0. IMO, we probably have more people that play just singleplayer than both those combine so I'd say at a minimum we have 1000+ users that have played some form of TripleA in the past few months.