Now that grandparents routinely use services like Facebook to connect with their kids and grandkids, they are potentially exposed to the Internet’s panoply of jerks, racists, creeps, criminals, and bullies. They won’t continue to log on if they find their family photos sandwiched between a gruesome Russian highway accident and a hardcore porn video. … So companies like Facebook and Twitter rely on an army of workers employed to soak up the worst of humanity in order to protect the rest of us. And there are legions of them — a vast, invisible pool of human labor. Hemanshu Nigam, the former chief security officer of MySpace who now runs online safety consultancy SSP Blue, estimates that the number of content moderators scrubbing the world’s social media sites, mobile apps, and cloud storage services runs to “well over 100,000” — that is, about twice the total head count of Google and nearly 14 times that of Facebook.