The notion of fan films goes back pretty much to the beginning of film itself. Thomas Edison himself famously filmed “a liberal adaptation of Mrs. Shelly’s famous story” called Frankenstein in 1910. However, the cost of production was too high for most people throughout the 20th century, and it’s only fairly recently that the it became feasible to stage a film of any length for anyone without a good amount of cash and/or ready access to film equipment. Thus, it’s only really be fairly recent that movie studios have had to contend with fans filming derivative works that could conceivably mistaken for officially sanctioned ones.
As an example, there have been fan films of Star Wars since the movie’s debut. Hardware Wars was released late in 1977, mere months after A New Hope first hit theaters. But the explosion of Star Wars fan films didn’t really hit until the early 2000s. This was due, in part, to some technological advances in wat could be done with home computers, but in larger part due to a fan film called The Dark Redemption which was written as a sort of prologue to A New Hope. Initially, Lucasfilm saw it as a very real and direct threat to their Star Wars property; it was generally regarded as the first serious and well-executed attempt to expand on the Star Wars universe. Prior works were either obvious parodies or simply executed in such a way that there would be no confusing it with an official Lucasfilm release. (That’s a nice way of saying that they weren’t very good.) The Dark Redemption, while still not quite up to par with the technical sophistication of ILM, presented itself very well and could conceivably be seen as fully sanctioned prologue to the original film.
There was some legal wrangling and a fair amount of posturing, but ultimately it came down that (allegedly) George Lucas himself said that Star Wars fan films were okay provided there was no attempt or intent to make money from the works. Having said that, and in light of what fans saw was capable in The Dark Redemption, the number of fan films exploded. Not just Star Wars, but with virtually every movie and TV show that had a fan base at all. Indiana Jones, Ghostbusters, Back to the Future, Batman, Lord of the Rings… the owners of those properties have largely remained silent on the matter, but seem to have taken to following in line behind Lucas as fans took Lucas’ tacit approval to everything they loved.
Of course, that’s not to say everyone takes that approach. The producers of the fan film Axanar based on the Star Trek mythos had a suit filed against them, bypassing the more typical cease-and-desist approach that concerned rights-holders usually take. Why it took over a year and a half for CBS to respond seems unclear (the original 20-minute Axanar “prelude” was uploaded in mid-2014, just weeks before their Kickstarter successfully ended with over a half million dollars) and if it signifies another shift in the legal approaches rights-holders will focus on remains unclear.
Regardless of where this ends up, though, I suspect it will be considered a significant marker for how other IP owners handle fan films going forward, in much the same way that Lucas set the tone for the past decade and a half.