Sadly, blocking seems to be the only way we can stop them ruining our blogs. Akismet works perfectly, it blocks 100+ spams a day. However the bandwidth is wasted, although the amount is not much.
I tried to find out who requested wp-comments-post.php more than 5 times before 18th of November. The results more than 100 IPs, I denied them in .htaccess. Less than 7 days, the number of last 15 days spams dropped from 1500+ to 850. If there is a WordPress plugin can use Akismet’s data to block, that would be more efficient. Yes, this could be my next WordPress plugin.
Updated at 12/10: I have unblocked those IPs for few days, interesting thing is the Akismet blocking count didn’t increase. Now is around 100. I wonder if spammer’s programs record were they blocked?
LLBB 