Earned Referring Domains

The word earned is doing all the work. A referring domain count that includes purchased links measures budget, not authority.

Measures

Distinct linking domains, separated into earned and placed, with the earned trend as the signal.

Data Source

Referral traffic in server logs, plus a link index for coverage of links that send no traffic.

Indicates

That somebody found the property worth referencing without being asked.

What Moves It

Publishing something specific enough to be cited. Generic content cannot earn links because there is no reason to point at it rather than anywhere else.

Does Not Prove

Ranking benefit, and certainly not the magnitude of one. It indicates that a reference happened.

Status

Partially measured. Earned versus placed requires judgement, and any third-party link index has its own coverage limits.