I have tried numerous searches for entries which should (and do!)
exist in Wikipedia, but, for some bizarre reason, the search
mechanism can't find them.
For example, I entered "your show of shows" (the classic TV comedy
show, starring Sid Caesar, et al.), both with double-quotes and
without, yet the mechanism fails to find it! However, when I
enter "sid caesar", lo-and-behold, "Your Show of Shows" appears
within the found list.
This isn't the only example.
Try it with "all in the family", "big world little adam" (I found
it once, but can't find it, now!), etc.
OS: Windows XP