In an article published this November, a recent survey by Kaggle uncovered that R is the most frequently listed tool in user profiles for Kaggle predictive modeling competitions. Of the 1,714 users that participated in the survey, R was listed as a tool used by 32% of users surveyed. Matlab finished a distance second at 13%.
Of the Kaggle users surveyed, inclusion of R in their list of tools was over 350% greater than inclusion of SAS. Kaggle also reported that 50% of competition winners used R in their analysis. Below are the survey results as published by Kaggle:
The above graph and the original story may be found at: http://blog.kaggle.com