It's a bit of a necessary inconvenience these days -the CAPTCHA on web forms to make sure whoever is filling it out isn't actually a spam bot - but over the last couple of years, you may have noticed the CAPTCHA challenges themselves becoming easier and easier, to the point where, a lot of the time, all it takes is for a user to tick an "I'm not a robot" check box. Soon, thanks to machine learning, even that won't be necessary. Google has announced the Invisible reCaptcha which claims to identify bots without explicitly setting challenges to users.