I have some problems with spam in the comment area in WordPress (this blog). So I started to look for a plugin that could handle this. I have seen that people use captcha (images with letters that you should insert when submitting a post) plugins but since I think that some people might have problems reading the letters I don’t want to use it.
So I looked at another plugin called Did You Pass Math?. It works but has some issues. For example if you write a comment and forgets to fill in the field for the answer you will lose the data.
Then I found out that WorPress actually have created a technique where they will match comments against a database. The plugin is called Akismet and is installed by default in WordPress. All you have to do is to register on WordPress.com to get an API Key.
I hope this will solve the problems!