In the Drupal development mailing list there is a discussion about date formats. Somebody suggested the ISO YYYY-MM-DD (or YYYY/MM/DD) format and most developers seem to like the idea. For example, it was proposed that 2005/11/27 is much better than 27/11/2005.
Although I personally use dates like DD/Feb/YYYY (i.e. the month being a name not a number) on my site, and I believe this format is better, I would like to introduce this argumentation (with the French meaning of the word) here.
Please tell me what date format do you consider "official policy" in Wikipedia and why? What is the most culturally neutral format?