DIDs can potentially be discovered from other identifiers such as HTTP URIs, domain names, or email addresses, using e.g.:

• DNS entries in a domain name's zone file (see here for a draft spec).
• HTML code embedded in a web page (such as a Verifiable Credential stating that "Domain example.com is run bydid:example:1234.")
• WebFinger

We should discuss if and how these protocols should be specified, and what implications (if any) this has for the DID Resolution spec.

Also consider "backreferences" from a DID to those other identifiers that point to a DID.