WLIT obviously did well with the Christmas music, but their ratings may have not been high in the beginning. As I said, it most likely increased each week closer to Christmas.
Recently, All Access has a story up about Arbitron's PPM testing in Philadelphia and Houston showing that stations who go all Christmas don't see a ratings spike until after Thanksgiving. To make their point, they gave a couple examples of average quarter hour shares for the 25-54 demo. One of the examples is WSNI. (BTW, Arbitron made these 2002 numbers available to the public, so it's ok to share them here.)
PHILADELPHIA
Persons 25-54
MONDAY-SUNDAY 6a-Mid
WSNI AQH
10/31/02 1.0
11/07/02 0.8
11/14/02 0.7
11/21/02 0.8
11/28/02 2.1
12/05/02 2.4
12/12/02 3.0
12/19/02 3.6
12/26/02 2.8
01/02/03 1.0
This may not necessarily be the story for WLIT, but it's still interesting.
BTW, WSNI has since flipped to another format (as you can see, the all Christmas listeners didn't stick around!)