Wikia management decided last year not to allow any more Wikia sites to take up Semantic MediaWiki, because of apparently insoluble problems. As our expert staffer said, "SMW is tough to run on a wiki, it's almost impossible to run effectively on a farming platform like Wikia."
At that time staff remained "committed to keeping it active and useable on wikis that already had the tool". A recent staff posting may even cast doubt on its retention: could StructuredData replace it?
See w:c:smwtest:Wikia's current approach; and please feel free to comment on that page's talk page or that wiki's forum.