I've recently updated to the latest WordPress and Akismet plugin. Since the upgrade a lot of spam is getting through temporarily. That is, I get emails to moderate comments, but when I go to mark them a spam they are either in the trash or spam folder. This wouldn't be a problem except that I get many thousands of spam comments in a month, and that is a lot of email notifications.
When I check the blog, there is a message about how Akismet is having trouble and comments are being held for moderation, but when I check my Akismet configuration everything is green and running fine.