Nighttimer, good points.

Fanfic, it seems to me, is on part of a larger phenomenon. It begins with girls playing with dolls and dollhouses, boys playing with the same thing but called something different to distinguish it from GURRULL stuff: "action figures" not "dolls," etc.

Then there's adult fanfic of a sort such as Fantasy Football.

To me fanfiction is like a sandbox where we can build sandcastles and the like. Which we can then tear down and build into more sandcastles.

A fair number of pro writers played with fanfiction before they became serious about their writing. For us the fanfic was practice. Because it wasn't SERIOUS we could experiment, make mistakes, turn out stories and story fragments which occasionally surprised us with its brilliance, all the more bright by contrast with most of our not-very-good material.

At first it is just play. Then, for some of us, it becomes something more serious. Something we, eventually, have no choice to treat as a profession. To graduate from the sandbox to the architectural college of Absolute Write then into daily and weekly work.