PregSpam is a wordpress plugin ,with which you can write your own regex to anti-spam.

For example,you can write a pattern "#company#" to test the author name.If match,author may be the spammer of a company ,then wordpress will do what you defined(wp_die(),mark as spam or mark as unapproved) in PregSpam.

You can

• define the type of the comment to be tested: trackback,normal comment
• define different fields to be tested: content,author name, author url, author email
• define different matching behavitors : wp_die(),spam,unapproved,approved
• define match or not match to be the condition
• define priority to order patterns
• write a msg to display when wp_die,even more you can write some variables such as content,which will be replaced with the content of comment