Thanks @bmann.ca. Yeah I’ve had my head deep in implementation stuff since getting back from Europe and done a bad job keeping up on forum discussion!
If I’m being honest, I’m not quite sure on this. I’d rather get away with not needing a notification. Right now, there are basically no vectors on the PDS for an “unsolicited push”. Those generally tend to accumulate spam and you have to start building defenses for them, which is difficult to do generically. This would open up a vector for that. Space spam where someone keeps adding you to a bunch of spaces and clogs up your PDS with nonsense spaces that you have access to.
It’s also a bit tricky because “membership” is fuzzy and not really a protocol concept. It could be temporary, driven off of some application semantic, or require a particular client.
In many cases, I think this can be solved at the application layer. For instance, if you use the same application as the creator of the space, then that application can help give the notification. In my current draft for atmospheric communities, I’m going to propose a “invites” space hosted by each user that communities can write into to deliver an invite (I’m more comfortable with this because it’s in userland & thus can be interpreted by applications as opposed to in the protocol).
Do you have a particular usecase in mind that could motivate this?