By only supporting binary versions that they have supplied to enterprise customers, [open source enterprise vendors] have taken away the advantages of open source from the customer. What open source does for [the vendor] is give them a cheaper way of developing their software by allowing people to take the community code and enhance it, and they get the benefits of those enhancements. [...] An enterprise has to be prepared to ensure that the enterprise open source vendor they are dealing with is really as open as they need.
He closes with a checklist which helps to receive all advantages and freedom open source software.
"Probably the best operating system in the world is the [operating system] made for the PDP-11 by Bell Laboratories." - Ted Nelson, October 1977