Once, browsing the server’s log file, I noticed a visit from Google. Someone mistyped the word “captcha” as “capcha”, and by accident I mistypes this word in a post too. Now I decided to look at the popularity of possible misspells.
* captcha — about 46,700,000
* capcha — about 579,000 (Google suggests the correct spelling.)
* captca — about 3,300 (Google suggests the correct spelling.)
* kaptcha — about 3,920 (the project name)
* kapcha — about 16,600 (the project name, not related to captchas)
* kaptca — about 228 (Mostly login names. Google suggest the correct spelling.)
According to Google, 1.2% of people misspell “captcha” as “capcha”. Other possible ways of misspell are not popular.
The second experiment was with Technorati. It returned 5,378 results for “captcha” and 86 results for “capcha”. Surprisingly, the percent grows: 1.6%.