If you use online forms it's likely you've used a 'captcha' (Completely Automated Public Turing test to tell Computers and Humans Apart) system that prevents a computer script from using the form to send out spam.
Google has acquired reCaptcha, the captcha system that not only prevents spam but at the same time uses the text you type as the digital substitute for that word - basically the words you see as an image have been scanned from books that are being converted to a digital format however some words cannot be recognised effectively by OCR (optical character recognition) and so the words you type are substituted in. Make sense? No? Ok, maybe the short video below explains it better...