This is an idea coming from Google Plus, though I never really used it (G+ that is).
Seems Quite intuitive though:
When posting a submission, it would be amazing for the person submitting it, to promote and/or change visibility to specific groups/users. This goes hand in hand with the already suggested "group" feature.
For instance, this could work the following way: Patrons on Patreon can see pictures first (delayed publication might also be an option here, for instance to support regular comic page releases), friends can see submissions first, long term/recurring commissioners see content first, etc. Or Commission can only be seen by friends because it is personal, etc. There are a lot of different scenarios to utilize such a feature.
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