Sharing communitites is definitely on the to-do list. At the moment each client has their way of providin a URL-path to these. Ideally it will be a "naddr", which will be a uniform way to share communities and post across Nostr.

Sharing posts is already possible as these are simple kind 1 events. here's your post's noteID: note1lfvwfuamtf0vlwpc6ccmuavn2nh06w5guews8ukrw4s4ahveda7qs23g6z