CAPTCHA Roulette

I vividly recall creating my Windows Live account and wondering how many folks are able to guess the 8 character CAPTCHA on the first attempt. I swear the CAPTCHA presented to me looked like random scribbles in a box. I did take screen shots but they seemed to have disappeared just like my patience on the day of signup.

Yesterday, I revisited the page and came up with the following examples. I don’t think these samples are THAT bad, but can you decipher any of characters strings with 100% confidence? I doubt anyone can and I think this feat is well-known to be impossible.

Have a look at all the help one gets. For one, the “8 character” hint helps a lot. And if you are still stumped, a new CAPTCHA can be requested until one becomes answerable. And if that fails, take a whack at the audio version in order to validate being human.

Coding Horror had a nice write up on CAPTCHA Effectiveness a while back. The claim was that even the most basic, most ineffective form of CAPTCHA, “naive CAPTCHA” where the CAPTCHA term is the same every single time, stops 99.9% of content span.

Granted, these statements were written before Coding Horror had 103K subscribers. I suspect this was well before Coding Horror needed to be overly concerned with telling computers and humans apart, but I think the sentiment that CAPTCHA doesn’t need to overly inconvenience the user to be highly effective still applies.

I am not opposed to extreme CAPTCHA — especially when hints are provided — but the extra clicks and guesses bugs me enough to go into a useless rant about Y’s, I’s and J’s…