Here's a great example about how YouTube is becoming the top choice when people search for videos - at least funny ones. A Hitwise entry shows that searches for "funny videos" have been falling while search for "youtube" have become more frequent.
Muhammad Saleem notes that while we can't forget the "correlation doesn't imply causation" rule from statistics class there does seem to be a correlation in this case. Note: This data is UK specific so it may not correlate with search trends in the U.S. and other countries.
