We as fan writers are taking a canonical universe and creating branches off that, little "what ifs" for our own enjoyment. Sometimes we enjoy pretending that our "what ifs" are part of the series, using them to explain things that happened or add poignancy to particular moments, to increase our enjoyment of the series based on the memories of the stories we've created. And sometimes we create a "what if" so extreme that clearly it doesn't fit into the series canon.
When fanfic feeds off itself, usually it follows the first pattern. Either the first story was part of the canonical universe As Explained By Writer X, and then the second story fits into both Writer X's and Writer Y's personal canon... or the first story was a what-if, and the second story was By Writer Y, Set In Writer X's Personal Universe. The main reason we do this is probably to avoid confusion. Having an alternate universe of an alternate universe of an alternate universe is asking for trouble.
Mercutio and I clearly must like trouble, then. :-) After I began writing my novel Only Human (based on the premise that Q lost his powers in Deja Q and never got them back), I began to be plagued by ideas that couldn't be done without the backstory I'd set up, but couldn't fit into the canonical Only Human universe, either. What if the Andorian who'd tried to kidnap Q succeeded? What if Q and Harry Roth made the beast with two backs? What if Queria Lang (an original character of mine, who appears in one chapter of PropinQuity) came to the starbase and met Q there? What if the Cardassians had kidnapped Q? And so forth. I never did any of these, because I was afraid they'd be hopelessly confusing.
Mercutio, inspired by Only Human, and depressed at the fact that hundreds of pages had gone by and Q hadn't yet had sex :-), sent me what was to become Chapter 1 of PropinQuity, expecting that nothing would come of it. In it, she introduces a character to save Q from the despair that led to his suicide attempt, Naomi Allen. I liked the story considerably, twisted her arm into posting it, and then sat on her virtual doorstep like a puppydog with my tongue hanging out until she wrote more chapters. 28 of them, in fact. They're available at my "Deja Q spinoff" site, http://www.alara.net/trek/dqtree.html, at least until such time as she might get around to posting them here.
Now, of course, I began to spin "what ifs" involving Naomi (ooh-- a new character to torment! :-)) I tossed one of them at Mercutio and she ran with it. Thus was "InseQurity" born.
At some point we decided that it would be tedious to do more "Q's first relationship" themes in IQ, since that had already been done in PQ and will be done again in OH, so we decided to incorporate another what if I'd had for some time, the one about Harry Roth (a character I created, a gay physicist with a talent for witty repartee) becoming Q's lover. I wrote "The Night They Drove The Borg Down", and we incorporated it as backstory for InseQurity.
For those who care, these are the sequence of events and the places the universes split:
First there was Deja Q. All Only Human universes split from Deja Q.
Then there was the Deja Q Addendum, the flashback in Only Human that explains how the events in Deja Q got changed, and Q's first days on the Enterprise. This includes Guinan kicking Q in the crotch. All Only Human universes incorporate this.
Then there was the Battle with the Borg. Q heavily participated in planning and strategizing for the battle with the Borg, and as a result of his involvement, Picard did not become Locutus, and there were lighter casualties at Wolf 359. All Only Human universes incorporate this.
The first split happens at the party right after the Battle with the Borg. In the Only Human universe, Q goes to bed alone. In "The Night They Drove The Borg Down", he goes to bed with Harry Roth.
In all universes, about a year after that, Q was attacked by an assassin and Security Chief Ohmura died. As a result, Q was beaten up by Security. In the Only Human universe, Q managed to call for help after his attack; in "InseQurity", Dr. Allen finds him. "InseQurity" takes place in the same universe as "Night... Borg."
"PropinQuity" takes place close to a year after this event, and splits off when Dr. Allen invites herself into Q's life.
"Only Human" itself begins with the death of Picard and Q's suicide attempt. Picard's death does not occur in any of the other timeline splits.
For more information, check out the "Deja Q Tree" at http://www.alara.net/trek/dqtree.html, which will also bring you to an archive site containing all these stories.
InseQurity is rated R for some small amount of sexual content, and fits into the hurt/comfort genre, though most of the hurt is emotional. It is written by Alara Rogers (who is posting it here) and Mercutio.