I could argue HN is pretty bad for my productivity, and that of many others. :-) But sometimes I unearth the kinds of things here that save me months of work. As bad as SNR is here, it's worse elsewhere.

Have you ever been to the "job rumors" forums like econjobrumors and PSR? It's like HN on steroids. Polite because it's semiprofessional and everyone's pseudonymous but can get easily outed from details (I mean come on how many people have been in strategy consulting and done graduate work on symplectic manifolds?) but also everyone's mean and competitive.

HN is less toxic than PSJR because the field it covers is much larger and positive-sum; academic job rumor forums are much more fish-eat-fish.