The first is Tiki Wiki. I had used it long ago and it was a pretty amazing collection of bugs. It seems to be stable now so I took another look. It is clearly not for everyone but, it is interesting for a certain class of users with a certain set of needs.
It is an everything including the kitchen sink project. We are talking 1,000,000 lines of code. If you are looking to do something small and/or uncomplicated, don't bother looking at it. Further, if you are not into Wikis, don't bother looking at it. And, if you don't want to spend some serious time with the admin interface, look elsewhere.
You are probably wondering what good it might be. Well, if you want the kitchen sink (blogs, forums, file uploads, photo galleries, surveys, polls, ...) it has all that and more. But, for good or bad, the pages of the site are done in a Wiki. Thus, you can construct a complicated set of pages related however you want (just like any Wiki).
That's the short story. Making the story longer isn't worth it. If the last paragraph described your needs and fits your abilities, look at it. Otherwise, find something else.
The Cotonti project seems to be on the other end of the spectrum from Tiki. The product is small and everything I have looked at is very clean. Being clean starts at the appearance of a default site and goes inside to the admin. While I have not (yet) created a site with it, I was impressed with the feel of the project.
Even the forums seem to be populated with helpful people asking and answering the right kinds of questions. It does have a plugin framework and plugins seem to be appearing for that which makes sense.
Note that there is an older version plus a new version, Siena, about to be released. Unlike other projects (Drupal is a good example) where new versions tend to lack all the modules you want, Siena seems to be getting new modules even before the final release.
If I was to look for something to compare Cotoni to, it would be Linux back in the good old days when the community was relatively small but lots of people were there pulling for the common good instead of trying to figure out how to make a fast buck.
I am still pleased with ocportal as I said in the previous article. It is well-designed, well-tested and well-thought out. While the user community is small, because of its commercial use, it does a lot with the minumum about of admin overhead.
Having spent many years being what the State of Washington called a "Systems Design Specialist", I just want to emphasize that there is no substitute for figuring what you want to build before you start building. A day, a week or a month, depending on project size, on a Functional Specification can save so much time and frustration when you are trying to get those square pegs into round holes.