Pine

Pine's development and usage is largely owned to the fact that it relies on self development of the many users and the community, in which this type of information is exchanged and circulated and therefore the upgrades and bug-fixed versions get to the end user.

   Outlook Express

Microsoft mostly develops, upgrades and bug-fixes itself and then makes the new versions of Outlook express available to the public, on their own or on other websites. But there is very little self development that the users can carry out on it, largely due to the fact that Microsoft's product's source codes are not open and because Microsoft wants to benefit from selling or marketing the upgrades of the software versions.