Well, although confusing, those two articles you mentioned are both correct.
There is no charge for the server software itself, but you have to pay a per
user license for each of your contribute users to access it.
I have more of an issue with the fact that nothing seems to work, it will not
connect to AD, it will not send email notifications to users when pages are
updated, and I can't really see any reason to have purchased it if those two
things won't work. I could have saved some money and just used contribute as
is. The only thing that it has helped with is that you can setup users on the
server instead of for each site, which does make maintenance easier. However,
since I can't interface it with AD, I had to create usernames and passwords for
43 people to access their sites.
Also, be advised that you have to open up either WebDAV or a file share to
give access to the users, which means that even if you have Contribute locked
down, they can easily go to the file share and edit the files with any other
program they want, or with WebDAV they can edit files over the internet simply
by dragging and dropping into an IE window. I was expecting a server component
that would work with IIS/Windows and lock down the site so that the only way to
access the site was through Contribute.
I am very disappointed.