Thread:Sannse/@comment-34924658-20141010023129/@comment-1038387-20141010222916

You don't. Memory alpha existed on that domain before it was acquired by Wikia, and part of the deal was probably that they kept the url. If you want such a url... you'd have to buy your own domain, set up mediawiki software, build a community, and hope you get gobbled up by Wikia.