This is easy to demonstrate - go to Tiddlywiki website and type macro into the search field. There is a note in that Tiddlywiki titled Macros, which is naturally expected as the top result. However, it appears in way down, in search results sorted alphabetically. While you can change the sort order of search results to other parameters like creation date or modification date, there is no way to sort it by "relevance". The third party solutions for this problem depend on creating and recreating index on every single change, which is inefficient and balloons the size of wiki.
Also see: