I have my weblog from about two years, but only few months ago I started to use it "hard" :-)
In Truden Web Site I've never had a problem with spam.
Obviously phpNuke is quite different than WordPress.
After getting tired with all the spam Akismet was catching I moved to Spam Karma.
Better, but I still had bin full of spam.
Then I decided to convert TruBar, which I made for phpBB2 and phpNuke in a WP-plugin.
Few hours work and it was installed.
The SPAM stopped.
Bu-u-t not for long.
After about 24 hours I had spam waiting on the moderation queue.
That was strange, because I can give 100% guarantee that no bot with OCR can brake TruBar's image.
When I checked the logs I saw that the SPAM went trough, bypassing the security check.
In my DB there was image record five hours older than the SPAM record.
All image records are deleted on successful use and with the successful image are deleted all image records older than one hour
So, the bot posted without generating image for security check.
That led me to the answer, which is:
WordPress let the SPAM trough on POST and then stop it with Akismet.
Very clever way to make use of Akismet.
I checked wp-comments-post.php and even I'm carpenter I could see that there is no any check that could be referred to the "good" word.
After some research I fixed it for my needs and the SPAM dropped to one or two on 24 to 36 hours.
Good, but wasn't good enough for me.
I DO NOT WANT SPAM in my weblog.
Then I changed TruBar.
No security image check.
And Tru comes from Truden, which in Bulgarian means difficult.
Now I have my TruBar stopping all the SPAM.
I made it as standard wp plugin and the size of it is 2(two)KB.
I won't tell you now how it works.
Come to test it in http://mnogo.truden.com say your word, and bring some SPAM bots with you.
I want to test it HARD before I release it.
Love to All.