Try to search for the word no. You'll get the message about needing to specify at least one keyword. WTF?
Just for laughs, try searching for see next. No matter how many times the word see appears in your topics, the search engine will report no hits. WTF?
On a related note, how do you search for not? (At least I can understand why this fails: because not is a "special" word; I still can't understand why there's no way to do it, though...like enclosing it in quotation marks, or something.)