Fans are made on youtube, fb and twitter also and none of these are community building sites, just social platforms. Community is when everyone knows everyone else. Fan base is when fan knows you.
Yes, curation reward is shared that way. I didn't get your last statement though. Why do u think it is different.
With that lets say a new user probably has a vp of 10 or so and SP of 40 will he/she still get any curation reward from the above explanation even though his upvote did not add any reward to the post