Google's John Mueller said technically you can use the knowledge graph ID URL for the URL in your SameAs property but it is not recommended. It is not recommended because that ID might change, so you probably want to use URLs that are less likely to change than the knowledge graph ID.
The question was asked at the 49:09 mark in this past Friday's video. The question was "Can we use the google.com kg mid ,essentially kind of a specific url for for knowledge graph entities, I think, as the schema.org sameas property."
John said "as far as I know you can do this" but he later said "I don't know if it's a good idea." It is not a good idea because "the knowledge graph ID that we have on our side it could change over time." Instead use contact page URLs, Wikipedia page about your company or something more stable that what Google might use in its knowledge graph.
Here is the video embed where he said this:
Here is the transcript:
Can we use the google.com kg mid ,essentially kind of a specific url for for knowledge graph entities, I think, as the schema.org sameas property.As far as I know you can do this. I don't know if it's a good idea though. Because essentially the knowledge graph ID that we have on our side it could change over time and when you're looking at something like the same as property in structured data you really want to provide something that is stable. Something that always remains the same so that over time we can kind of associate more and more things with that. And if you assign something that is generated by Google which theoretically could change over time then that feels a bit, i don't know, brittle and it feels like something that could break over time. So I as far as i know, I would would try to avoid doing that and instead do something like pointing at your contact page or your website's homepage or a Wikipedia article about your company or anything like that which is something that is more more stable than the the knowledge graph ID.
John was additionally asked about this comment on Twitter:
I'd ask @danbri before accepting too much of what I say about structured data -- maybe he can help with a more official & complete answer on whether it makes sense to use google kgmid URLs for sameAs.
— 🧀 John 🧀 (@JohnMu) September 3, 2021
If we don’t mention it in our structured data docs, then that’s a clue that it might not be a high impact thing to focus on (although harmless)
— Dan Brickley (@danbri) September 3, 2021
We aren’t going into more details on this currently
— Dan Brickley (@danbri) September 4, 2021
Interesting...
Forum discussion at Twitter.
Note: This was pre-written and scheduled to be posted today, I am currently offline for Rosh Hashanah.
