I currently lead a Diaspora group. Diaspora is a hard science fiction Fate-based RPG which allows and basically depends on the generation of content like worlds, cultures, NPCs etc. by the players.
I noticed in the last few session that often someone mentioned some cool aspect of the world but due to the flow of the narrative we (myself in particular) forgot to write it down. We have a wiki to put such stuff in, but that doesn't help if no one adds it.
Are there any techniques or table rules that have been proven to be helpful to preserve ad hoc made up aspects of the game world? As in, "someone who creates something has to write it down," or more technical aids like recording the session?