AbdulAlhazred
Legend
Ditto. It's way over at the 'collaborative storytelling' end of the spectrum.
You'll definitely get a sense of authorship, and I can see how this could absolutely rock as a one session one-off with a decent group. But in a continuing game or campaign I'd sure hate to be the poor schlub who has to remember or write down everything said and done and authored this session so it'll be consistent when we come back to it next session...or next month...or next year...
There are some games I've read about which have a more structured approach to who gets to invent the narrative, what they can do with it, etc. which probably are much more RPG-like, but still provide some fairly significant opportunities for players to 'write a story'.
You could add some elements like this to 4e probably (though this is beyond what I've experimented with so far at least). For example you could let the player describe the narrative consequences of defeating an opponent (4e already allows a limited version of this by RAW). So you could let the player state something like "the orc is utterly disheartened and gives up as I hold my dagger to his throat. He throws down his weapon and raises his hands." This is a SMALL example, but it could be expanded to things like describing the narrative consequences of victory or defeat in an SC (this might not work in a DM-centered mode of play, but it COULD work in a Story Now type of game). You'd probably put some hard constraints on exactly what the player can describe (perhaps there would need to be a formal staking of assets at the start for instance). In fact I could imagine a sort of 'bidding' type of SC where the players could be authoring as much content as they want to 'buy'. Of course the GM will be enriched or the player's become poor in some sort of plot currency in this process. I think it would work pretty well in 4e though without a lot of reworking of the basic mechanics of the rest of the game.