Seconded. Ycombinator is fine here, in my not-lawyer opinion -- as far as I've noticed (as someone who blocks first party cookies by default with uMatrix), they

Seconded. Ycombinator is fine here, in my not-lawyer opinion -- as far as I've noticed (as someone who blocks first party cookies by default with uMatrix), they set only a single cookie, when you log in. I checked just now and it has only two pieces of data: your username, and what looks like a signature for validating it.