Dhanushka Samarakoon <[log in to unmask]>
> Confluence is free for non-profits, but for academics they charge a reduced
> fee. http://www.atlassian.com/licensing/confluence
> 
> If you just want a basic wiki mediawiki would work, but for more elaborated
> access control (and other features) Confluence would be better.

Atlassian are particularly insiduous, using dodgy tactics like free
"first hits" for FOSS projects and non-profits to try to get people
hooked and keep them away from the community using and improving free
software.  I've lost count of the number of times that I've heard
librarians criticising similar divide-and-conquer marketing efforts
like free-to-university-libraries from library service providers,
so I'm surprised to see people recommending it here!

I'm no big fan of mediawiki (mainly because its markup is incompatible
with earlier wikis, which confuses me every time), but it has a vast
range of extensions, so it's definitely not basic.  Much better to be
part of an information-sharing community, isn't it?

(I use trac's wiki and mediawiki on various projects.  I've contributed
to a few projects that use Confluence, but really don't like it.)

Hope that helps,
-- 
MJ Ray (slef), member of www.software.coop, a for-more-than-profit co-op.
http://koha-community.org supporter, web and library systems developer.
In My Opinion Only: see http://mjr.towers.org.uk/email.html
Available for hire (including development) at http://www.software.coop/