How "I'm not a Robot" checkboxes work

Zuck That says, "Have you ever been on the Internet when you came across a checkbox that says Im not a robot? In this video, I explain how those checkboxes (No CAPTCHA reCAPTCHAs) work as well as why they exist in the first place."

I mention CAPTCHA farms briefly, but the idea behind them is pretty straightforward. If a company wants to create an automatic computer program to buy 1,000 tickets to an event or make 1,000 email accounts, they can make a script that fills out the form one at a time, and when the program gets to a CAPTCHA, it will send a picture of it to a CAPTCHA farm where a low-wage worker will solve it and send the answer back to the computer program so that it can be used to finish filling out the form.