Get an Akismet code from wordpress.com and enable Akismet which should be installed by default on your WordPress blog. If you don’t have it, you can get it here http://akismet.com/Â .
captcha-free
Is a very easy to use plugin, all I have to do is install it on WordPress, and activate it. I haven’t gotten a single automated comment spam since installing it on this blog. I use to get 1-4 automated comment spam a day. now I have zero.
Best of all, users do not have to type in a captcha code to post comments.
You can also go into your discussion settings f0or wordpress under Settings Disscussions to reduce pingback and trackback spam.