I think they mean manually labeling data en-masse. Maybe tagging photos with a description of what's in it, as a common example. "Turking" is probably a refere

I think they mean manually labeling data en-masse. Maybe tagging photos with a description of what's in it, as a common example. "Turking" is probably a reference to Amazon's Mechanical Turk service, where you can to get lots of low-effort work done by people.