Mmm webposter privacy seems right, they just have an nsec derived of a password so if you know the password you can post, no more info needed. But this is basically symmetric encryption, while if you use the relay I made it would be like asymmetric, since posters just post using the nsec they control and the post will be resigned when broadcast to the mixer relay. This may be chaotic, so the relay also allows you to define a whitelist of pubkeys that can publish, which is not public, and will be the equivalent of share the password with the people you want to publish in the webposter example. Also the relay I made can expose the notes through http without need to interface with any other piece of software. Which is very convenient, and also allows you to expose the mixer relay through tor and automatically you can have a deployed blog over tor that you can interface by just sending notes. Hope all of this doesn't sounds confusing xD