Akismet have announced Version 2.5.3 of the Akismet plugin for WordPress
Akismet blog says, There are three changes in this update:
Specify the license is GPL v2 or later
Fix a bug that could result in orphaned commentmeta entries
Include hotfix for WordPress 3.0.5 filter issue
For those that have experienced issues with your commentmeta table growing in size, this update addresses that by making sure we don’t create orphaned rows in the table.
If you have automatic updates configured you’ll see the update in your dashboard soon.
More info and download: http://blog.akismet.com/2011/02/08/akismet-plugin-version-2-5-3-for-wordpress/