What is the technical name of that class of tool that pops up 5 to 6 images and asks you to pick all the 'xyz' items from that list? CAPTCHA is text on a funny background and you are asked to read that text and type it as an answer to unlock some part of the web-site - this however is asking you to identify some subset of images as verification you are a human.http://i3.kym-cdn.com/photos/images/newsfeed/000/963/262/259.png
What's the technical name of the captcha like thing which asks you to identify all the 'ice-cream' pictures?
spam prevention;validation
This kind of spam prevention is usually provided by the reCAPTCHA service from Google. IMHO this is an advanced spam protection service based on the principles of CAPTCHA. While I do not think reCAPTCHA is a technical name and there could also be other advanced implementations of CAPTCHA-like spam protection.