In comments to my previous post, Lucas Johnson described the loose outline of a non-ARG transmedia experience in which players might construct fictional personas, and in which there is ambiguity regarding which characters are players vs. game designers. We took it to email for a bit, and Lucas graciously agreed to let me share my response with a wider audience.
So there are a couple of different things involved here.
1. It's incredibly hard to get people to produce content. Incredibly hard.
We ran a column contributed by players once a week in the Perplex City Sentinel for two years. We had tens of thousands of registered players, and many weeks we had no columns submitted. Asking a player to fabricate a persona is, in fact, asking them to make user-generated content. There are cases where collaborative worldbuilding works, and it's a sandbox I like to play in myself sometimes, but it's not at heart a strategy that will hit the big time for you.
Think about the ratio of people who watch a TV show vs. the ones who write fanfic for it and you'll get a general idea of how few people are interested in this kind of play. You can't just say "OK, come build a world with me." You have to give an audience something to love and care about first.
2. A structure like this isn't going to scale up very well past maybe a few dozens of players, tops. You'd have to manually keep tabs on what your community is up to, which costs man-hours if not cash, and the more players you have, the harder it will be to keep them in sync.
Look at what a mess comic book continuity is; and that's a bunch of people who are getting paid cash money to stay consistent with one another. In a conflict, who decides what is and isn't canon? And how is that information propagated?
3. Liability. This isn't as much of a concern financially when you're an indie designer trying to make art, but the habits you make now are going to stick with you when you're successful. If a player has no way of knowing if a character is YOU or another player and hands over a cell phone number, or goes to what they think will be a dead drop, and The Worst happens, even if you are not found guilty of accessory in a court of law, you are going to feel pretty awful.
This is absolutely not a boundary to mess around with. You have a responsibility to protect your players, even from one another. And that's not even going into my usual liability patter, which is about your obligation toward people who might stumble upon pieces of your experience and not know that they're just pretend.
So that's where I come down on this particular issue. I'm open to the idea it could be handled responsibly, but I'm at a loss as to precisely how; if any of you have more concrete suggestions, as always, please do weigh in in comments.