Know instantly if a profile is already on your people or artist lists (in-feed indicator)

Executive Summary

Many power users and professional curators—roughly 150 million globally who actively manage people or artist lists—spend minutes to hours a week checking whether a profile is already saved, across multiple networks, and face discovery friction, duplicate follows, and curation fatigue as a result. This problem is amplified as decentralization (Bluesky, Mastodon) spreads profiles across instances and platforms, making a single, instant view of "already on my list" hard to achieve without sharing sensitive follow lists. A practical solution is an in-feed indicator that shows in real time if a profile appears on any of a user’s people or artist lists, implemented with privacy-preserving methods such as on-device hashing, federated matching, or homomorphic techniques so raw lists never leave the device. The product would be lightweight—a subtle badge and one-tap actions to add/remove or jump to the user’s list—and would need connectors for major networks, client SDKs for third-party apps, and fallbacks for API-restricted platforms. The timing is favorable: this is a roughly $6.0B market (150M social power users × $40 ARPU/year), with a Market Score of 88/100 and Revenue Potential of 78/100, and trends like on-device AI and curation fatigue creating demand for a small UX-first utility. To stand out you should emphasize a privacy-first architecture, open standards for cross-network matching, and excellent micro-UX rather than trying to be a full social manager; realistic challenges include platform API constraints, the engineering complexity of secure matching across federated networks, and the need to persuade client apps and power users to adopt a new indicator. Overall, this is worth pursuing as a niche cross-network utility if you can secure early integrations and demonstrate clear privacy guarantees and time-savings metrics.