I don’t know how long this option has been in Akismet, but there’s now a checkbox labeled Automatically discard spam comments on posts older than a month
.

Following the recent WordPress 2.6.1 upgrade, I noticed the option when reactivating plugins post-upgrade. I checked it, and my incoming spam trap has been squeaky clean. This is better than turning off comments; anything that I’ve ever written here has comments open, so someone with something legit to say can still say it, irrespective of the post’s age.

Thus far, it has been a win-win, and far fewer spam comments to trudge through looking for false positives. I’ve had precious few of those.

Thanks, Akismet!
-k-