Here is a nice page by Bob Muenchen (author of “R for SAS and SPSS” and “R for Stata” books)
It is available at http://r4stats.com/popularity and uses a variety of methods, including Google Insights, Page Rank, Link analysis, as well as information from Rexer Analytics and KDNuggets.
I believe the following two graphs sum it all up:
1 Number of Jobs at Monster.com using keywords
2 Google Scholar’s analysis of academic papers
Despite R’s Rapid Growth which is clearly evident, in terms of jobs as well as publications, it lags behind SAS and SPSS. So if you are a corporate user or an academic user, it makes sense to have more than one skill just to be sure. What do you think? Is learning R mutually exclusive and completely exhaustive from learning SAS or SPSS. See http://r4stats.com/popularity for the complete analysis by Bob Muenchen
Also it shows the tremendous opportunity for companies like Revolution Analytics and XL Solutions ( http://www.experience-rplus.com/ ) as the potential for growth is clearly evident.