The image of Santa Claus holding bottles of coke and the magical sparkles surrounding the logo and truck, these things are all there to create a feeling of happiness, like it states in the headline. The main purpose of this ad is to make you feel like in order for you to share happiness with your loved ones this christmas, you better give them some Coca Cola. The subliminal "messages" in this ad will prove very successful for people who enjoy Coke, but this is about as deep as I feel those messages go.
For people who are not loyal to a brand, keeping with my example of Coca Cola, these ads will not successfully get them in the store buying the product. If some one just simply does not drink soda, specifically Coke, a nice whimsy picture of Santa Claus is not going to have much effect on them.
Subliminally it may still evoke the same emotion of happiness and that general Christmas spirit, it's not going to make the, change their opinion on the product.