You probably haven't seen PimEyes, a mysterious facial-recognition search engine, but it may have spotted you. If you upload a picture of your face to PimEyes' website, it will immediately show you any pictures of yourself that the company has found around the internet. You might recognize all of them, or be surprised (or, perhaps, even horrified) by some; these images may include anything from wedding or vacation snapshots to pornographic images. PimEyes' decision to make facial-recognition software available to the general public crosses a line that technology companies are typically unwilling to traverse, and opens up endless possibilities for...