Matt Cutts Captcha Validation

Matt Cutts has written a post about his new Captcha that is now accessible and will make it harder for ‘Spam Bots’ to dump nasty comments on his blog. What Matt has implemented is quite a neat idea as it allows the visitor when posting a comment to answer a small maths question to ensure validation of a ‘live human’ such as the following example:

Sum of 5 + 7 ?

There is a slight problem with this captcha. that given a few hours most programmers could sit and write a script that would defeat Matt’s Captcha validation and extract the two numbers from the question probably after a few hours.
Furthermore once this is widely used then the protection goes as it becomes even easier for a bot to challenege the script (or rather worthwhile).
Matt could look at the following for an idea where it set up with about 5 or 6 lines of text like this:

“Thank you for reading the Matt Cutt’s blog
and interest in this post ‘changed my captcha
Please feel welcome to leave a relevant comment.
Thanks for writing!”

Question: “What is the seventh word on the third paragraph?
Choose a letter from this word?”

This would work quite well, while it is a bit more tedious it would certainly be harder for a Spam Bot to break. Having said that, nothing is safe online whatever you come up
with there will always be something there to break it (eventually).