Wikis, websites designed for the communal creation of media content, have previously been theorized using the work of Levy (1997) as knowledge communities. In this conception, wikis are seen as storehouses of data that communities can use to organize and explicate their encyclopedic “communal intelligence.” This paper expands on Levy’s argument to examine the narratological possibilities of wikis. Using as examples fan-created wikis for the cult television shows Lost and Heroes, it is shown that these media-based wikis highlight the fan community’s interactive construction of a narratological database. Using the interactivity omnipresent in wikis, fans articulate a new conception of narrative construction, a conception termed here “narractivity.”