Years ago there was a television ad for an antidepressant that asked a simple question: where does depression hurt? The answer came back flat and certain — everywhere. It was effective advertising, in part, because it named something true. Depression isn't only sadness. It's a kind of physical weight, and people recognized it when they saw it described that way. There is a comparable weight carried by people living with chronic and rare disease. It has no thirty-second spot.

There is a number that keeps coming up in online communities. Ninety percent. Ninety percent of members never post. Nine percent contribute occasionally. One percent create nearly everything everyone else reads. Usability researchers call it participation inequality, or the 90-9-1 rule, and it has been documented for decades across every kind of forum, group, and comment thread that exists. In most contexts, this is an interesting footnote. In rare disease, it means the major