During the time of that post, this article was about a simpler example and only explained the trie structure. Wade didn't have the ranking system either. It has

During the time of that post, this article was about a simpler example and only explained the trie structure. Wade didn't have the ranking system either. It has since been rewritten to include the methods used to rank the relevance of a term to the document, and to see how they are applied in a more complex example.