Are you sure you also spelled canceled wrong? If you did spell it wrong (the way the OP did), then the search must be intermittent:
Yes, I'm sure I spelled it the same way the OP did. I did notice and remember the two l's in "cancelled".
My theory about the question mark is wrong. I tried a different thread with a question mark and it worked fine. So there must be some other reason why it doesn't find the Daily Show thread with "cancelled" as part of the search.