Slash community involvement: creation. (It is not necessary to have shared these creative works with the public or with anyone else.)

Hmm. I may have misread your comment above, but it seems you're defining slash community as only those who have created fan works (whether public or in drawer-fic/art)? I'm hesitant to define slash fandom (or fandom at large) to only those who create fan works when plenty of us get involved in fandom in other ways.