GreyThing is an experimental approach to social and messaging infrastructure built on a simple premise: users should be able to keep identity and data when they move between providers, apps, or domains.

The key idea is cross-domain portability of identity. In most systems, portability exists only within one ecosystem: you may switch servers, but not move cleanly across domains, providers, or application contexts without losing continuity. GreyThing explores a model where identity stays stable while hosting, storage, and software can change.

In this talk I will present the core architecture: DID-based identity, signed objects, user-owned storage, capability-style grants for private data, and DID recovery through a quorum of trusted DIDs. I will also cover the hard parts honestly: discovery, indexing, migration, abuse handling, and the tradeoff between protocol purity and usable products.

This is not a “replace Mastodon tomorrow” pitch. It is a proposal to treat the social web as portable infrastructure instead of platform silos, and to discuss where this model can realistically complement existing Fediverse systems.