The strongest piece of evidence cited by believers in phone eavesdropping is a leaked pitch deck from CMG Local Solutions (a Cox Media Group subsidiary) that described an "active listening" ad product combining voice data with behavioral data. However, CMG subsequently distanced itself from the claims, and no independent researcher has verified that such a system exists or operates at scale.
On the refuting side, a rigorous Northeastern University study analyzed over 17,000 Android apps and found no evidence of covert microphone use. Technical experts at Mobile Dev Memo note that always-on audio capture is implausible at global scale — it would drain batteries noticeably, require large data uploads detectable by network analysis, and risk immediate app-store removal. Mark Zuckerberg explicitly denied microphone use for ads under Senate questioning in 2018.
The "eerily accurate" ads that fuel the belief are fully explained by metadata: location history, browsing patterns, purchase records, cross-device tracking, and behavioral profiling. These data streams are so rich that advertisers can infer conversations indirectly — no microphone required. The evidence, in sum, strongly supports metadata tracking and strongly undermines covert listening.