HI @mrkvon !
ActivityPods are limited Solid PODs so, if in WelcomeToMyPlace, you create an account on the mypod.store provider, it will create your own POD. You will then be able to do all the normal LDP operations like GET/POST/PUT/PATCH/DELETE, either in Turtle, triples or JSON-LD (like required by the Linked Data Plateform specs). Additionally, WAC (WebACL) specs are fully supported. On the other hand, WebID-OIDC login is not supported yet, and users cannot create their own containers (containers are created by the apps).
At the end of my presentation at Solid World, I talk about how we could make this software evolve so that it’s compatible with existing Solid providers. The easiest solution would be if these providers supported an ActivityPub-like inbox and outbox (which I heard is in the box…). But in either way, some challenges would need to be tackled.