Also, allow me just a quick addon to which people probably aren't responding in the comments below. I assure you banks and the like using R aren't passing round

Also, allow me just a quick addon to which people probably aren't responding in the comments below. I assure you banks and the like using R aren't passing round all their R/python/C code either. R didn't bring open source to science. It brought free (as in price) software to stats, and that, along with its script-like ability to apply formulas quickly, its vast library, and its universal teaching in stats courses in universities, is the reason for its popularity. I'd even go so far as to say that python has had more of an influence outside of stats/bio/pharma. But spend a bit of time in the SAS community to which it is commonly contrasted and you'll see massive amounts of code sharing, examples and how-tos. The interesting thing is to observe how these things play together. I argue that sharing of source has less value if the run-time on which it operates is not available to you. Of course, SAS is so widespread in big business that you might point out that it quite clearly is available to a lot of people, and that it quite clearly is valuable to them, its just not available if you can't pay or aren't in a connected uni/job. I know my SAS and I can do several things in it that whip R and python's butt if the task is that which SAS is good for. It has its own separate and relevant issues in terms of design abd implementation. I can rail against all the tools i use :P But the high-entry-cost of the software itself is the prime reason I'm trying to turn my back on it (because I don't plan on being employed by a big company or being locked into a software vendor forever, and subsequently it is not available for me to use for my own projects, which are often more valuable/complex than the ones i'm writing for employment...). I imagine there are a large number of other programmers/hackers feeling the same way, and you might even say that its evidenced by the parallel (as in along-side SAS, not multithreading) success of R. Perhaps there is a symbiotic relationship, subsequently, between free as in price vs open source code. Who knows. I need a "free as in beer"....