A WikiBlog is anything that combines the features of wikis and weblogs together well, imho. Same as WikiLog. Maybe.
Some implementations have modifications to the wiki, some don't. I suggest you look at some of the software listed at AbbeNormal:WikiWeblogs and the specific wiki-weblogs at http://sknkwrks.dyndns.org:1957/writewiki/wiki.pl?PublicWikiWeblogs (BrokenLink) -- JohnAbbe
A blog on a wiki. Try out PikiePikie.
Or IkiWiki's page aggregating features.
Some differences between wikis and blogs can be found on WikiIsNotYourBlog.
See BloggedWiki