As some of you may have noticed, this site was having 500 internal server errors earlier this evening. WordPress was running out of memory, and it seemed to be plugin related. I moved all of the plugins out of the plugin folder and it started working again. By reinstalling plugins one at a time I was able to isolate the problem.
It turned out to be Alex King’s Twitter Tools. When I tried to enable it in the plugin page, WordPress reported a fatal error and didn’t enable it. I tried a different Twitter plugin, which seemed to work until got the same error when I published this post and it tried to send a tweet, The real problem was that somehow the PHP version reverted to 4.4.7 instead of 5.2.2 in Dreamhost’s domain control panel. Changing it back to 5.2.2 corrected the problem.