The Song of Yendor is a case in point. It is a novel who's idea came to me when I was 15. (Back then the hero's name was Eric.) I've written the 1st chapter many times and now I just write a story from the endless epic whenever it hits me. I call that a chapter & hope that one day there will be a narrative there. (This link contains stories from another book Into the Woods that is being written in a similar fashion, but is not an endless epic.)
Zazzle, Greeting Card Universe, Etsy and the like.
Tumblr would be a perfect venue for this kind of work.