@abundance
The measure is community value consensus - it is in the community's best interest to reward content based on its impact to the community, and curators are rewarded proportionately to the impact they discover.
Community & curators can up/downvote curations, which affects curator allowance (curators want to maximize their allowance to earn more, so they need to ensure their curation aligns with community values.
A community can also set criteria on who can curate to ensure alignment and quality.
More on this here:
https://paragraph.xyz/@abundance/how-impact-works