After spending 3+ minutes trying to prove to a site (Patreon) that I was a human being by having to solve CAPTCHA, it finally realized that I was human because it gave me one where they used one photo broken into segments and I had to click whatever subject they wanted. One of the problems with CAPTCHA images is when they use multiple images and put parts of the subject (crosswalk, bus, car, stoplight, etc.) and you click too many or not enough to qualify as being human. Store fronts tend to be the best as do the ones when they use different images instead of one image that is broken into multiple images where you have to choose the items. The same goes when they use letters/numbers and make them hard to determine what some of them are.
Here’s Wikipedia’s definition of CAPTCHA : https://en.wikipedia.org/wiki/CAPTCHA
This user identification procedure has received many criticisms, especially from disabled people, but also from other people who feel that their everyday work is slowed down by distorted words that are difficult to read. It takes the average person approximately 10 seconds to solve a typical CAPTCHA
Even for perfectly sighted individuals, new generations of graphical CAPTCHAs, designed to overcome sophisticated recognition software, can be very hard or impossible to read.
I am going to include ReCAPTCHA https://en.wikipedia.org/wiki/ReCAPTCHA, No CAPTCHA reCAPTCHA (variation of ReCAPTCHA – and I clear out my cookies multiple times/day), and any similar alternatives in the mix.
Another big issue is they don’t work. The goal is to:
The main purpose of a CAPTCHA system is to prevent automated access to a system by computer programs or “bots”. On 14 December 2009, Jonathan Wilkins released a paper describing weaknesses in reCAPTCHA that allowed a solve rate of 18%.
The above is from the ReCAPTCHA Wikipedia link above. If you read either of the Wikipedia links, it shows ways around the problem although those won’t work for many of us.
When I said they don’t work, it’s because the spammers have ways around them and the bots are getting better at figuring out the system.
Here’s a great blog post on the subject: http://www.seosmarty.com/impossible-captcha-it-doesnt-really-matter-if-you-are-human-or-not/.
To add my two cents to this question: https://www.neogaf.com/threads/the-select-all-images-with-a-street-sign-recaptcha-is-a-godless-creation-of-evil.1410504/, it seems sometimes they want you to include all of images that don’t really fit (traffic lights may or may not include the pole they are attached to).
My favorites are the ones where you simply click the I am not a robot and it automatically lets you hit submit.