What? WP was certainly not the first cms/blogging tool, not even the first to reach mainstream popularity. Blogger was arguably the first offering "blogging for non-nerds", Movable Type was the first to reach critical mass among nerds, and the very first "blog engine" was probably Manila. WP wasn't even the first to have plugins, although it was probably the best implementation yet (and one of the main reasons behind its success). If you extend the search to generic CMS engines, there is also stuff like PhpNuke, Plone and the other "portal-like" tools which are even older.