A popular, full featured wiki written in Python.
MoinMoin homepage: http://moinmoin.wikiwikiweb.de/
MoinMoin uses content blacklist using regular expressions. There is a global blacklist, hosted at http://moinmaster.wikiwikiweb.de/BadContent, and maintained by users (see http://moinmoin.wikiwikiweb.de/EditingOnMoinMaster). Wikis update their BadContent? copy automatically. There is alos a LocalBadContent, used to block local content which may not be relavent to other wikis.
Antispam is built in from version 1.3 (current version is 1.5.7). It is disabled by default, becasue it requires reliable internet connection, which may not be available on intranet wikis. It is also possible to use antispam on 1.2 version.
To enable antispam, see http://moinmoin.wikiwikiweb.de/AntiSpamGlobalSolution.
There's discussion about other possible features at: http://moinmoin.wikiwikiweb.de/AntiSpamFeatures.
See also the general AntiSpamRecommendations