I wish you wouldn’t move the challenges to DA. I’m hesitant to create an account there just to be able to submit something that can be easily submitted via tumblr (like usual) and the mods can upload it on DA as well, for all I care. Is there a possibility to submit (any) content solely here?

Yes. In fact I mentioned it in this big long message full of important things here: http://30minchallenge.tumblr.com/post/110469352215/the-roundup-begins

Everyone should give it a read over if they haven’t.

Also art is up on DA!