Simply terrible. This is a sample of a CAPTCHA shown to users of German file-sharing service Rapidshare. In case you skipped over the first part (as I did at first) to enter the letters shown, you’d be wrong. You have to work out which letters are hiding a cat and which ones are hiding a dog and only enter the ones with a cat.
A CAPTCHA is a program that protects websites against bots by generating and grading tests that humans can pass but current computer programs cannot. The idea behind such a device is to prevent scripts, spammers, search engines and other unwanted automated visitors from getting behind your page, the most visited sites on the internet implement some kind of CAPTCHA (yahoo, facebook, myspace, hotmail, gmail etc).
Sounds sensible does it not? It is highly sensible except that it has developed into an arms race of sorts as news of the recent crackings of Gmail’s Captcha, Yahoo’s Captcha and frequent crackings of Hotmail’s Captcha show. What this means to the end user is that CAPTCHAs increasingly get harder to solve. Facebook was caught out by a particularly unfortunate CAPTCHA bug as shown below.
I don’t think any of the above efforts have yet proved to be a viable replacement and sadly I can only see the arms race waging on for a couple more years yet. Still RapidShare has sucessfully implemented the worst CAPTCHA I have ever had to deal with on a regular basis so far! Where will the madness end?