If you can recall the number XXXXXXXXXX, but you attach no significance to the number, you have mere knowledge. Not tremendously useful, is it? However, if you are familiar with a particular song...

If you can recall the number 8675309, but you attach no significance to the number, you have mere knowledge. Not tremendously useful, is it? However, if you are familiar with a particular song performed by Tommy Tutone, you may recognize this number as the telephone number of a girl named Jenny, which the songwriter had found penned on a wall.