I'm just curious as to how people found out about this site, so I'm running a bit of a survey here. Basically, if someone has provided an answer to the titular question already, upvote it. Otherwise, post your own answer! After about a month or two (providing I remember), I'll update this question with a pie graph of the results. Thanks for participating!
I came from StackOverflow. I've been there for several years, and one day I was reading down the hot links down the right side of the page (I had never really paid attention to the sidebar for the longest time) and saw something interesting. Star Trek, maybe? Wheel of Time? I could wish for more Heinlein discussion, but he's my favorite author, so I'm biased.
Anyway, that's how I got here.
While out xmas shopping, I was taking a short break and browsing the news on my phone. I spotted a clickbait article about the "top 100 essential sites" (according to the Guardian Newspaper) and followed a few different links, including the one to SFF:SE.
I think I actually joined the following day.
I had been rewatching the original Star Wars trilogy and suddenly realized that R2-D2 tries to trick Luke in Empire Strikes Back, and I wanted to find somewhere to ask questions about Star Wars. This was the best place I could find. I joined the site and asked the question linked above, and the rest is history.
I first found out about this site through the Movies & TV Stack Exchange, where this site and its partial overlap was brought up now and then during the early days of meta discussion. I didn't join this site until about 2 years after finding out about it, though.
Found out about this site via the main Stack Exchange sites; Stack Overflow, Super User, etc…. I have contributed to this site on and off over the years, but mainly have been an active reader of the content here: No kidding, some of the questions and answers here are great!
As of the last few weeks, far more active thanks to The Force Awakens being released and Star Wars being more in the spotlight. For the first time in genuinely decades I have deeply thought about certain aspects o the storyline I have not thought of.
And as a result I am part of that “weird” aspect of the Star Wars fanbase who only really cares about Star Wars (1977) and The Empire Strikes Back (1980) and really was disappointed with the childish/pandering tone of Return of the Jedi.
But that said, being back on the site has made me appreciate the universe of Star Trek far more than I did before. And I have some deep respect for a few of the regular contributors here.
That said, if I were not an active member on Super User and other sites I will honestly say I might only have been a reader of the content here. So to me the unique aspect of the Stack Exchange system is it took me little to no effort to link my account up here and decide, “Well, let me try my hand at a few questions or answers here…” So kudos to the whole Stack Exchange eco-system for allowing enthusiasts of all levels to participate in discussions across various topics!
From The Screening Room.
I think Keen (or maybe someone else) mentioned it in chat with pro-temp mod of Movies & TV on various occasions few years back.
I was trying to find the answer to a question, one I'd had for several years - googling around various keywords. One of the links was to a question on the site. It was not actually relevant to the question I had - but I realized I could write my own question. Unfortunately the question that brought me here is not so easy to answer, but so it goes.
The Force Awakens came out.
I was already participating decently actively in the Myth.SE.
Then, I was probably looking around in people's profiles(AKA being a stalker), and I see a SF&F.
This will finally meet my questions for The Force Awakens!! Yessss
And so I join
I came from MathOverflow of all places.
When I first joined that site, it was an independent site using an earlier version of the Stack Exchange software. Later, the owners signed a deal to join it to the Stack Exchange network, with a few special arrangements remaining. This was sort of a big deal at the time, so obviously I found out about the other Stack Exchange sites. Of all the sites, Sci Fi became the one that captured me, because I already had a liking for Harry Potter and for western sci fi books.
Like others, I started with the main Stack Overflow site (although they claim my Super User account is older) and branched off to here. I want to say that the English Language SE was the one I went to after that, then it gets fuzzy. I came here via a sidebar advertisement and now it's my primary haunt.