"Popularity" depends on the community and the definition of "statistics".  World-wide, taking a broad view of "statistical inference" as including any methods of drawing conclusions or taking actions based on quantitative data, there is little question that **[Excel][1]** [beats][2] all other applications, including [R, SAS, Stata, SPSS, and S-Plus][3].  (The links point to different kinds of statistics, but they are highly suggestive, to say the least.)  Python and MATLAB aren't even blips in the statistics.  I am not saying that this is a good thing or that we should like it: that's just how it is and that's how it's going to stay for a very long time.

We shouldn't draw any inferences from what may appear to be popular "here" in this forum.  Commercial software vendors support their own forums, so naturally a place like SE will favor people using less actively supported software, especially free, open-source, and academic solutions.


  [1]: http://www.pcworld.com/businesscenter/article/166123/forrester_microsoft_office_in_no_danger_from_competitors.html
  [2]: http://blogs.technet.com/b/office2010/archive/2010/06/15/office-2010-availability.aspx
  [3]: http://www.kdnuggets.com/2010/06/software-popularity-of-data-analysis-software.html