HN is open in almost every sense, and it exists within an open market...

[1] Open vs Closed System (social science) https://en.wikipedia.org/wiki/Open_and_closed_systems_in_soc...

[2] Open System (systems theory) https://en.wikipedia.org/wiki/Open_system_(systems_theory)

[3] Open System (computing) https://en.wikipedia.org/wiki/Open_system_(computing)

[4] Open API https://en.wikipedia.org/wiki/Open_API

[5] Open Market https://en.wikipedia.org/wiki/Open_market