The aim at AMO Open Science is for exactly that, consequently almost everything on the boards is fully open to non-members.
The notable exception is the Events, links, videos and such (members only) forum, which does exactly that, and is only accessible to registered board members. Use this for anything that is only for forum members directly, e.g. links to talks, Zoom meetings, file share links etc. (Note, however, that since anyone can sign-up to the board, this is still a relatively public forum in principle.)