So, what's the Lunaverse, anyway?
The popularity of My Little Pony: Friendship is Magic has led to the creation of lots and lots of fanworks. Some of these fanworks became more and more famous in the community, eventually spawning what Tvtropes calls 'recursive fanfiction' - fanfics of fanfics. See, for example, Fallout: Equestria, and Story of the Blanks, both of which have spawned numerous derivative works. Some of these works even incorporate the other stories into their canon, such as Pony Fall and Chess Game of the Gods. These are called shared universes; worlds where the original author is allowing others to write stories based off of their fic which are 'canon' in their fiction's universe
The Lunaverse is one such universe. It's a collection of stories, written by multiple authors, which take place in the same 'universe'. The stories can build on each other to form arc and long-term plots, yet they can also be written by multiple authors, allowing for a wide variety of people to participate in the world.
The backstory and lead-in to the first story of the Lunaverse, as described by the universe's originator RainbowDoubleDash, is:
[CW for these two paragraphs only: some links contain ableist language]
"1,000 years ago, Princess Celestia, who governed the day, grew power-hungry and wrathful, becoming the evil mare of fire and hate: Corona, the Tyrant Sun. She had to be sealed away by her younger sister, Princess Luna, who has reigned alone over the land of Equestria for a millennium. Now, however, Corona has retuned, and it is up to Princess Luna's student, Trixie, and five other mares of extraordinary character - Raindrops, Lyra Heartstrings, Carrot Top, Ditzy Doo, and Cheerilee - to stop her machinations."
After the first story, the canon stories mimic the format of the show's episodes, with both self-contained plots and longer story arcs. Stories are both based directly on show episodes (parasprites show up, as does a traveling mare named Twilight who dislikes Trixie's magic show and gets an ursa involved ), as well as new ideas created by the authors (Dinky wants to buy a present for her mother Ditzy, but the mare in charge of the jewelry store has a grudge against Ditzy; after a spell by Trixie transforms Lyra into a different body, Trixie and Lyra's marefriend Bonbon must help Lyra perform at an important concert) Mimicking the series, stories are called 'episodes' and divided into 'seasons.' Season 1 is nearing the conclusion now.
So that's what the Lunaverse is, but what makes it special? As mentioned above, there's a lot of MLP shared universes, and even more where derivative works are encouraged, if not canon. Why is the Lunaverse particularly neat?
1. The community. The Lunaverse includes a forum where the authors can discuss future ideas and the stories they are writing. This gives the community a much more close-knit feel than some of the other verses, where even when multiple people are contributing, they don't really talk to each other. It's a very supportive group who will happily proof-read and beta for each other, and will either praise good plots or help fix up bad ones. Discussions can get vehement sometimes, but it's still low-key; people disagree with each other on the direction of the verse as a whole or individual stories without it getting personal. This forum also gives the Lunaverse a vast richness of detail, since even non-authors can come up with ideas that are then incorporated by the writers. I find it neat that so many people can contribute to making something creative, particularly something as cool as the stories in the Lunaverse.
There is currently one group-written story, plans for another, and a few other collaborative projects in the works. But even the works entirely written by one author are still filtered through the forum, giving more of a community aspect to even the most independent of the stories. Some ideas currently kicking around on the board include the marriage of Lyra with Bonbon, the Grand Galloping Gala (which will feature Trixie going up against the first season's big bad), an episode where Carrot Top and Applejack take part in one of those dinner theatre murder mystery things, and a silly romp where Dinky and a few of her friends go on a Daring Do-esque treasure hunt through Ponyville.
2. Quality control. As much fun as it is to write for an shared universe, there's often the risk that the next writer will retcon the past story so that it was all a dream, kill off a main character and wreck everyone else's future plans, add pointless gore and make it grimdark, or just write something bad enough that no one wants to be associated with it. The Lunaverse, though, has fairly strict quality control standards. Works that get added to the canon have to meet the rating requirements (the vast majority of them fit the 'all ages' tag on the website), work with the canon (so one person can't take the story in a wild direction no one else wants to go), meet spelling/grammar thresholds, etc. It helps ensure that the Lunaverse will remain good, which influences me and others to be more invested in it and to keep contributing to it.
Stories that don't meet canon standards aren't banned or anything; they're just listed in a separate, non-canon section of the Lunaverse. So far, we've had one story moved to non-canon for changing the plot too much (Dinky got a ghost friend), one for canon problems (brought in changelings too early and didn't get them right), one for defeating the season 1 big bad before the end of the season (which would have weakened his arc), and one other for general quality standards. These stories can all still be seen (and several are enjoyable in their own right); they just aren't part of the canon anymore.
3. Similarity to the canon. A lot of the other shared/recursive fanfiction universes deviate from the canon in fairly major ways. A few examples:
[CW for this section only: violence, death]
Fallout: Equestria: After an apocalypse that wipes out pony society, one survivor emerges from a bunker and travels across the battle-ravaged landscape. Extremely violent and gory.
Pony Fall: Ponies are turned human and dropped into our world.
Chess Game of the Gods: Humans are turned into non-pony creatures like griffins, dragons, and diamond dogs, then dropped into Equestria by dracoequini who think that humans can make the world more chaotic.
Story of the Blanks: Apple Bloom goes to a Silent Hill-like town of ponies who killed a foal for superstitious reasons (she got her cutie mark, and they thought those were evil), and have been cursed to be monsters ever since. Follow ups usually focus on trying to save the town, or on the bad ending of Apple Bloom being turned into a monster as well.
I'm interested in MLP because I like the show, so I'm most interested in writing communities that actually correlate with what's on the show. I like the episodes, the solving of friendship-based problems, the happy tone, etc. So a universe with characters that do that appeals to me. It isn't that I don't necessarily like the other stories -- I actually really enjoy the original Story of the Blanks -- but I think the Lunaverse is more interesting to write/edit stories in.
4. Differences from the canon. That all said, I also like that the cast and problems aren't just like the main-universe cast 2.0. Trixie isn't Twilight; she has a different personality, retaining a lot of her traits from her episode in the show, while also having the other sides of her filled out more. She can be a braggart, prone to exaggeration about herself, but she can also be a true and loyal friend. She also has different goals than Twilight, wanting to eventually earn a seat in the Night Court (the governing body that's headed by Princess Luna), which leads her in different directions. Even her magic is different; unlike Twilight, whose talents seem to be conjuring and telekinesis, Trixie is an illusionist.
The same is true for the rest of the characters. Ditzy Doo (Kindness) isn't a copy of Fluttershy; she's more outgoing and confident, but also has some secrets in her past that have caused her to doubt if she really deserves her Element. Her being a single mother also provides for stories that Fluttershy's character doesn't. Carrot Top (generosity) lacks Rarity's fastidiousness nature, but also a lot of her business sense. She's a smaller-scale farmer than Applejack, and her envy of AJ's wealthy farm and her dealings with her are also used for some plot points. Similar things can be said for Raindrops (honesty), a rain-loving pegasus who takes great pride in her work, yet has some anger issues; Cheerilee (laughter), a fun loving teacher who knows how to party hard and who can be somewhat condescending, and Lyra Heartstrings (loyalty), a skilled, if lazy, musician who is deeply in love with her confectioner marefriend Bonbon.
There's also the differences in the setting. Since Trixie wants to be on the Court, we get to see more of how Equestria is governed. The political implications of six ponies having vast magical power are explored, as is Canterlot society, both in terms of ponies we already know like Fancy Pants (a rich pony heavily involved with charity work) and Blueblood (a politician), and new characters like the season 1 big bad Duke Greengrass. Since the Lunaverse isn't limited by things like an animation budget, there can also be more travel; stories and ideas so far include trips to the farming center of Trottingham, a small, poor village in the middle of nowhere called Oaten, the Spain-analog of Caballeria, and the isle of Tambelon, where Grogar (a villain from a prior generation of MLP) once lived. This allows for deeper worldbuilding.
Lastly, because the series doesn't need to be self contained to attract new viewers (since new readers can always start at the beginning), the Lunaverse can have plot arcs. There's been a couple so far, including Greengrass's machinations as he tries to control the Elements, as well as a shorter duo of episodes involving another side pony, Octavia Philharmonica. This again ties the universe together and makes it feel more connected, and thus more fun to participate in. The ability to write episodes out of order (the very first one written is about seventh chronologically) also lets the writers tie in later events to an earlier episode, to bring the world together as a whole.
5. It's fun to have a universe where characters can be gay (Lyra & Bonbon) or disabled (Ditzy, who has strabismus) without it being a big issue/deal, but just something that everyone accepts. As Ana Mardoll noted recently, a lot of works featuring marginalized groups are entirely about the marginalization, and while there's nothing wrong with that, it's nice to have something different too.
So that's why I enjoy the Lunaverse. I think it's got great stories, and it's a splendid and supportive community. The current canon list features a lot of really good stories. Any folks who write or read MLP fanfiction should feel free to check it out; it's a fun place, if I say so myself.
Tvtropes (includes summaries of all the stories so far and the characters):