ETA: See Damien’s comment below. Although I still see the ideas being used there, and I don’t think fan fiction means “unoriginal” or that writing it indicates a lack of creativity. However, since I apparently need to be disabused of this notion, sure, consider me disabused.
While I was reading some wank on fandom wank ((The type of wank currently featured on top is part of an entire tag/category: “writers are often pompous douches.”)) I found out that Shards of Honor, the first book in Lois McMaster Bujold’s major SF-award winning series, actually started out a long time ago as a Star Trek fanfic.
You can kind of see, in the first few pages, the skeleton of a Star Fleet officer and a Klingon warlord Meeting Cute ((Tropes are neither good nor bad; it depends on how the creator handles them. This is one that can easily be handled in a mediocre or boring way.)), but it’s actually good. I can see it now, and remembered thinking about Aral as “wow, I’m observing a Proud Warrior Race Guy in the wild.” Yet the “file numbers” ((File numbers: original characters you’re either using directly or as very obvious expys.)) had been filed off so well that I could only see the fanfic skeleton when someone mentioned it.
And shortly after the introduction of the two main characters, the story quickly veered away from “Starfleet and Klingon” and took its own course, with some vestiges here and there. And the entire saga after the first book definitely went its own original course; no more fanfic skeleton, or if there is, it’s been completely disassembled. It gained wings it never would have as a Star Trek fic.
Which just goes to show that (a) fanfiction can be good, (b) but original fiction can be much better.
So many people forget (a). Many fanfic writers forget (b).
Spontaneous ∂erivation 
You did not “find that out”, you heard a rumor that Lois denies.
Now, this Star Trek thing. This is going to be the third time I have knocked it on the head *this year*. It’s getting profoundly
irritating. *SoH is not now, and has never been, a Star Trek story.*
Six *years* before I started writing it, to entertain myself driving to
work, I had worked out a vaguely ST-universe two
enemies-lost-on-planetside scenario. You have only my word for this, by the way, as I am reporting on my private thoughts here. Nothing was ever written. When I did sit down in 1982 to write my original novel, I used some elements from this scenario in the opening chapters, while also drawing on not less than my whole life and everything I’d learned in it. By the time the first word hit paper, I wanted to write my *own* books, thank you very much. And I did.
While I do not wish to gratuitously insult Trek fans — I consider them a potential market for character-centered action-adventure stories with something of the same economic lust that early 20th Century industrialists used to look on the population of China, if only I could push my product across their mental barriers — the suggestion that one is incapable of making up one’s own stories is perhaps the most deadly insult you can level at a writer. Please refrain from doing so. And when you encounter this Star Trek rumor again — and it seems to be everywhere — kindly disabuse the perpetrators for me. I don’t seem to be able to catch up with them all.
http://lists.herald.co.uk/old-archives/lois-bujold/971016-918
Lois, back in 1997.