I just wrote a ten page essay. I won't torture you, but I think I can see now why people write books.
Instead of giving you a nice nap, I decided to cut out all of it except a challenge.
Of course, to get to the challenge, you have to sit through a page of detail...
My long-time readers might remember Livewire and Kung-Fu the Card Game the Role Playing Game (KFtCGtRPG). The challenge is to design a core mechanic which does what these games didn't quite manage. This is not an easy challenge. Here's more information.
KFtCGtRPG was a game based on kung-fu movies. You played with cards, a bit like Magic: the Gathering but more like Lunch Money. A fast-paced, light-hearted combat game where you gained experience to buy more stuff. It had a faulty negative feedback loop and no organization behind the plot/NPCs, but it was still a literal runaway success - the players started plotting against me to keep the game going.
The driving force in KFtCGtRPG was plot cards. I created a totally stereotypical kung-fu plot line, and made some 30 cards with snippets on them. Snippets like "The Iron Master uses only his legs" and "The Temple of the Unforgiven was raided four months ago".
The way I set it up, once you got a number of cards it started to all make sense. The plot was big enough that you had to have several of these "oh, I get it!" moments in order to really see what was going on.
I'm not just babbling, but now I'm going to go on another seeming tangent before bringing this whole thing together.
The other game, Livewire, was a vaguely similar game designed to run without a GM. It went exactly as I thought it would (meaning it died), but I gathered data from its death: it did not die in vain.
In this game, instead of having a master list of cards and a GM-built plot, the players got to make their own cards and plots.
The mechanic was fairly simple: every time you wanted to make a card, you had to have help from other players. The idea was to force players to get together and twist them into plots of their own devising.
I learned three very important things, which I'll just list quickly so that you can lust after an imaginary book. Or, I guess, I can lust after the book, and you can think I'm a shmuck.
1) Players need to be pulled into gamespace, and if it is multiplayer, they all need to be pulled into the gamespace.
2) Normally, history is lost as players leave the game, because most game histories are vocal. In a high-churn situation, this is unacceptable.
3) Very few players (<5%) have the capability to actively sustain a fantasy world. Most players will participate in a fantasy world, but not actively seek to produce or sustain a world. Most players who can sustain a fantasy world are control freaks and not suitable for sustaining a fantasy world heavily influenced by other players.
The last is what I'm going to limit myself to, even though the first two are equally interesting.
Almost all players are happy to participate in a fantasy universe, but there is a natural tendency for player-created universes to become either PvP or tightly controlled, depending on how much power the creator is given. Either way is unsuitable for most players, who want to be involved with other players but not in a way which risks anything.
Livewire actually did pretty well on that front, using a system of voluntary inclusions and requiring the use of other players in cooperative ventures.
However, Livewire's universe was... fragmented. There was no driving force, no overarching plot. This was mostly because plot couldn't be distributed: the networking was enough to make you touch a dozen other characters to get what you wanted done, but each of those other characters was only exposed to the tiny fragment of plot that you are working on them with (which was usually something on a lark, anyway).
On the other hand, KFtCGtRPG was exceedingly cohesive. This let the players (forced the players) to work together to conquer the universe or be defeated. It also allowed players to do whatever they wanted with their own characters - some had very nice plot arcs, and most had interesting moments, at least.
But, like Livewire, these were nearly impossible to share on a useful scale, and couldn't be interacted with by other players in any useful manner. They contributed to one player's enjoyment - and any nearby players who happened to be involved - but they didn't echo throughout the universe.
They should have.
How would you solve this problem?
Don't simply answer off the top of your head, please. This is an exceptionally complex issue. You have to make sure that a player's story can't be hijacked and, similarly, another player can't be forced into an irritating situation by that plot. But, the plot does need to be distributed. Not all players will actually see it, but they should all have the potential to see it, especially in parts of the game where they are not being exposed to much plot.
In addition, the plot has to allow for a high level of complexity. "Steve killed Bob" is not a plot. It's a blurb. The plot needs to be something that can be explored. "You discover a shattered sword. It has a red dragon on the hilt." Later, "Oh, Bob's symbol is a red dragon..." A slow unfolding of the plot is necessary to keep players emotionally interested.
Ha! And it has to be easy enough to do that more than 5% of the players will participate. Whether this is by automating it or simply making it extremely beneficial...
I have some ideas, but I'd like to hear yours.