There is an interesting letter (Let the four freedoms paradigm apply to ecology) in Trends in Ecology and Evolution by Duccio Rocchini and Markus Neteler arguing that science should use open source software. Basically, using open source software will help researchers to test, reproduce and build upon work of others, while being (more) sure that the code / algorithms they are using are robust and reliable.
Now, you could perhaps expect this article to be freely available. But try to get it from ScienceDirect and you’ll be charged USD 37.95! Luckily, as pointed out on the GRASS email list, you can get the article for free, just go to the website of Trends in Ecology and Evolution directly and read it / download it from there.
Interesting how ScienceDirect (Elsevier) is trying to generate income from freely available content.