OK admission. I am addicted to Mixel now. It's totally taken up all my FB time (thank you). And the chitchat is minimal. Mostly you just make stuff sort of together. Now the warning. Anything you upload becomes public property. I am mostly just adding a few detail images and nonart snapshots to the process. But I love the cropping and layering soooomuch. And I am printing some of these on fabric, too.
I have figured out how to use the software to make collages (fun-- crop with your finger or a sylus from any of your own photos or web images or images other Mixel users have contributed) without making images public or getting involved in the public arena of this software. You do have to have an account (no longer only possible with a FB account) but you do not have to post to "the world." After making a Mixel, just go to the upper left corner and take a photo -- saves to your ipad. Then DELETE the image.