Word verification for Comments

I have noticed on certain blogs that I frequent spammers are entering comments and links. I have set up through the settings/comments section of my blog "word verification". This setting asks the person adding a comment to my blog to enter the text displayed before comment can be added. Since spamming is mostly automated it cannot read the text and comments cannot be added. I hope this works, and suggest everyone turn this feature on to thwart the spammmers.