Measure real attention — track actual time spent on each browser tab

Many productivity and time-tracking tools log app or window focus but not which browser tab a user was actually attending to, producing inflated or misleading time data for the roughly 200 million knowledge workers who would benefit from more granular measures. This gap frustrates individual contributors trying to understand personal focus patterns, freelancers and agencies billing by time, and remote managers seeking passive, privacy-respecting accountability. You could build a lightweight, cross‑browser extension that measures per‑tab attention using visibility/focus events, input activity, media playback signals and configurable heuristics, doing most processing locally and offering optional anonymized, aggregated team reports and integrations with tools like Jira, Asana or Harvest. The market is compelling now: remote and hybrid work raises demand for passive measurement, privacy‑first preferences favor local‑first solutions, and the TAM is about $12.0B (200M workers × $60/year); the opportunity metrics (market score 92/100, revenue potential 90/100) reflect strong interest. That said, adoption will be slowed by browser platform limits and the fundamental difficulty of distinguishing active attention from passive consumption. To stand out, prioritize privacy defaults (on‑device processing, opt‑in telemetry), transparent accuracy claims and easy workflow integrations; competition is medium, but few competitors combine per‑tab granularity with privacy guarantees. Strengths include a clear billing and focus‑improvement value prop and low recurring infrastructure costs if you keep analysis client‑side, while honest challenges are proving measurement validity to skeptical users, ensuring cross‑browser compatibility, and addressing enterprise procurement and compliance requirements.