Professor Felten notes, eavesdropping on calls can be quite difficult due to language differences, meandering conversations, the use of slang or deliberate codes, and other attributes that either by design or accident obfuscate the meaning. “The content of calls are far more difficult to analyze in an automated fashion due to their unstructured nature,” he argued. By contrast, metadata is mathematical: clean, precise, and thus easily analyzed. And as Felten put it, it is often “a proxy for content”:
