A couple months ago, Technorati announced that users of Wordpress needed to upgrade to the latest available version (now at Version 2.5). This week, Technorati announced that blogs remaining vulnerable to identified security exploits may no longer be indexed by their service.
Because of this ongoing problem, we're discontinuing processing crawls of blogs that exhibit common symptoms of being compromised. We strongly recommend upgrading your WordPress installation. Even if you haven't been afflicted by a compromise, by the time you are aware that you have been a number of negative consequences may have already occurred (for instance, flagged spam by Technorati, Google or Yahoo!) -- this has been reported by many WordPress users.
By not upgrading your software, the search engine services may block your site from being listed. I can't think of a greater incentive to update your content management software to the latest version than the threat of being delisted. This is a bold move by Technorati. I'm personally glad Technorati is taking a stand against sites hosting older versions of Wordpress with the known security holes. In my opinion, there really isn't a good reason you shouldn't be upgrading your Wordpress site to the latest version.
Now that I've patted Technorati on the back for forcing Wordpress users to upgrade, I better quietly go verify that my own Wordpress site is running version 2.5. :-) Do as I say and not as I do...