Comparing Confluence with Basecamp is interesting because, as the blogger points out, while the two product’s features overlap somewhat, they really serve two different needs. MediaWiki and Twiki are also mentioned in this review that can be found on Code Intensity:
Confluence is a superb wiki! I’ve used several other wikis over the last year or two (we use twiki heavily as well, and I’ve tried a half dozen others). Confluence takes it up a notch. It feels polished and professional, and it’s been a joy to use. Also, the less-technical folks are finding it a lot nicer to use as well. And, their task extension (we’re using the Enhanced Task List macro) is quite nice, perfect for what we’re after (fitting our Scrum use).