The right metric is conversation quality.
At least for this kind of public thinking.
Reach is tempting.
Attention is noisy.
Performance can distort the thought.
The better signal is the conversation that follows.
Did someone useful reply?
Did the idea get clearer?
Did a better example appear?
Did someone connect it to a thread I had missed?
Did it open a real relationship?
That is harder to measure.
But it feels more true.
If the goal is to find people thinking about adjacent problems, then the metric is not audience size.
It is conversation quality.