gnuhoo borrowed the basic outline for its initial ontology from usenet. in 1998, rich skrenta said, "i took a long list of groups and hand-edited them into a hierarchy." for example, the topic covered by the comp.ai.alife newsgroup was represented by the category computers/ai/artificial_life. the original divisions were for "adult", "arts", "business", "computers", "games", "health", "home", "news", "recreation", "reference", "regional", "science", "shopping", "society", "sports" and "world". while these sixteen "top-level" categories have remained intact, the ontology of second- and lower-level categories has undergone a gradual evolution; significant changes are initiated by discussion among editors and then implemented when consensus has been reached.