This thing is based on MySQL's fulltext search. There are all sorts of subtle wrinkles with it, here are the main ones:
- i have it set up to use mysql's "boolean mode" and automatically put a + in front of all search terms. This seems to give more useful results, all matches have all keywords.
- results are sorted chronologically with the most recent first.
- you can put a - in front of a word to exclude it from the results.
- you can use * at the end of a word to treat that word as a prefix (e.g. rubicon* matches "rubicondom")
- you can put quotes around multiple words to match the exact phrase.
- the * doesn't work inside quoted phrases
- words less than 4 letters are ignored
- there are other words that are ignored, listed here