Google has updated its structured data documentation to now use hashtags for @id references. If you don't use hashtags, it is fine, but Google said it is "schema best practice to use hashtags as resolvable in-page node identifiers in RDF."
Google explained they have switched "all structured data code examples that use in-page @id references to use hashtags instead."
They did this because "It's a schema best practice to use hashtags as resolvable in-page node identifiers in RDF." Google said they want their "examples follow best practices."
Google also said, "You don't need to change your existing IDs if you're still using in-page identifiers."
What does this mean, here is a before and after example:
BEFORE:
AFTER:
Forum discussion at X.
