A private intention can change without anyone else noticing. A public pledge turns it into something other people can refer to: a promise to publish spending records, complete a contribution, or uphold a shared norm. That visibility may help others coordinate around the commitment and notice whether it is kept.
But announcing an intention is not the same as doing the work. Experiments on public recognition of identity-related intentions found circumstances in which recognition was followed by less intensive action. For a goal tied to becoming a particular kind of person, recognition may provide some of the feeling of achievement before the work is done. A promise to deliver something others can inspect creates a different relationship between the announcement and its audience.
What the audience can see
A volunteer group might publicly commit to publishing an expenses summary each month. The promise is concrete enough that members can tell whether it happened, and carrying it out provides something useful beyond the announcement itself. A commitment to publish public decision records would similarly give the audience something inspectable.
A vague pledge to be “a transparent organization” is easier to celebrate and harder to assess. Public commitment can also pressure people to persist with a bad plan because revising it would look inconsistent. Explaining legitimate reasons for changing a commitment can preserve accountability without rewarding stubbornness.
The mechanism is social visibility, not motivational magic. The audience, the specificity of the promise, available capacity, and what happens afterward determine whether a pledge becomes a useful coordination point or merely a pleasing statement about the sort of person or organization one hopes to be.