Are reputations earned and questions answered on Stack community considered as worthy publications?
Useful work in academia (I'm coming from a US perspective; perspectives elsewhere I think follow similar trends but may differ a bit) falls into three broad boats:

Research
Teaching/education/mentorship
Service/outreach

Publications fall under the category of &quot;research&quot;. Stack Exchange participation definitely does not fall under this category (except perhaps in the rarest of circumstances; I don't think those circumstances are much worth considering in any general answer given how rare they are).
Teaching/education typically considers activity within the university. That's the stuff that students pay for (or more generally, the university receives some compensation for the benefit of the students).
Service/outreach includes all the &quot;extra&quot; stuff academics do: it includes participation on faculty committees (service to the university) and also includes service to the broader community. If, for example, an academic volunteered at a local primary/secondary school, that would fall under &quot;service&quot;.
Service is almost certainly the least appreciated of the academic trinity, and service to the whole world is probably not weighted as heavily as service to the local community. Service in a local community or to the university itself is more easily justified to other stakeholders, like government officials who control university budgets. That doesn't mean it doesn't have value, just that it has the most chance to be undervalued.
Stack Exchange participation might, at best, be seen as a form of Service.