Collaborative Narrative System?
Whatever you call your product, it's going to say something about the way you view it and the way you intend others to view it.
This links in with beliefs, stereotypes and relationships as much as anything else in the product.
If you call it a "roleplaying game" it sets the product as fairly conservative. It fits in with the dozens of other products on the shelves, and thousands of games online that also call themselves roleplaying games. People who are familiar with this type of product know what to expect from it. A GM, a bunch of players a system for resolving actions and conflict, a way to set up scenarios. The game may have points of difference with the others (and hopefully it does, because otherwise there is no point in a consumer buying it or wasting their time on it).
If you call it a "story game", you start to enter a nebulous territory where different people will believe your game is something special and deviates from the mainstream in some way. It may no longer have a GM, it may resolve scenes and wide ranging conflict rather than specific actions, it may do something else differently. Either way, such a game will probably be perceived as less about the individual characters and more about the ongoing narrative potential.
If you call it something else, people have even less idea what to expect. Such a game stands alone in a crowd...but is this a good thing or a bad thing. If you want people to know what to expect, stick with a traditional title...if you're willing to risk people thinking your product is a pretentious pile of crap then by all means go with the arty sounding description, other people might be drawn to the name as description for an innovative piece of interactive art.
I'm not telling you what to call your product, I'm just saying to think about the ramifications of your choice.