I was very intrigued by the article “Why Heather Can Write,” and was surprised that there was no mention of the historical roots of fan fiction. Fan fiction is not a recent invention. The Aeneid is, in essence, a piece of fan fiction, taking a minor character from the Iliad and expanding upon his story (whether this piece of fan fiction shows signs of that other hallmark of fan work, I will leave up to your interpretation).
The recent trend towards a desire for every part of a story to be original is just that: recent. Most works that received substantial notoriety prior to the last few centuries were either retellings of existing stories or were advertised as such. Myths and legends are another example of “fan work.”
It is very interesting that the internet has provided an easy way for people to simultaneously return to an earlier model and drastically expand upon the way it works.