There are recent analogs to this multi-path narration. The now-dying medium that is dvd broadened with alternative endings, extras, commentary, games and connection to dynamic websites. It gave more choice to the viewer than we had ever seen, and what has evolved is a excitement to create alternative narrative paths for consumption. The goal should be to avoid making this a gimmick. Done well, it will add to the story. On the web, this information can be dynamic. Done badly, and distractingly, it can hurt the overall ideas the work intends to portray. Multitasking, where popcorn events interrupt important information, is different from complicating a narrative with multiple paths of navigation. Like journalist and media theorist Jeff Jarvis commonly says, this technique has the possibility to being disruptive.
This day did not answer the question of what will work using these techniques.
A second thought is that I hope it becomes commonplace for programmers and hackers to support people who craft stories. Not only do the artmakers get access to expertise that is otherwise expensive and rare, programmers get to interact with users. This was a notable success of the day. Hopefully these relationships stay strong.
I hope an event like this is done again and with the entire ITP community.