Confluence search sometimes returns results that surprise users. These tips are from support people who have helped users to understand search results.
Searching with quotes, for example searching for the string "Book One", does not look for an exact match like most search engines do. Rather, it looks for "Book AND One" and would return all matches where "One" is the first word after "Book" other than things considered to be stop words (a, the, an, etc.) This is explained in this support request: http://jira.atlassian.com/browse/CONF-7148
It's not possible for Confluence search to return hits for "the best," as an example--with or without quotes, "the" is ignored.
On the backend Confluence is using a search tokenizer called Lucene (http://lucene.apache.org/java/docs/). As part of its tokenization process, Lucene strips out all punctuation from the search string, including _ characters.
