#tags are not in use but are constantly being evaluated.
The search engine indexes any word with 3 or more letters.
If you search for something with 2 letters or a common english word, it will have annoyingly cut that word out, so "flames of war" or "skull of thrones" would return 0 results as 'of' gets cut. The best option is to do an advanced search for "+flames +war" and "+skull +thrones", but neither are ideal and that is a glitch I need to fix as that is the main source of confusion with the search engine.
Other than that, it functions normally. You can filter with the filter options, you can search the standard way for whatever you like, and only need to use "" and + and - when you are doing and advanced search. You can find a rough outline of what you can do with the advanced search here:
http://lucene.apache.org/java/2_4_0/queryparsersyntax.html