There are a lot of ways to figure out the most popular Christmas movies worldwide. You can look at box office sales, the number of times each movie has been streamed on Netflix, or relative popularity on the Internet Movie Database (IMDB).
Or you can look at how often each movie is pirated.
CEG TEK International, a copyright protection company, used its proprietary software to track how many times each of 33 classic Christmas movies was illegally downloaded using the torrent client, BitTorrent, between Dec. 14 and Dec. 18 of last year. Here is their list, ordered by number of downloads. (One obvious limitation is that it doesn’t include every Christmas movie, only a pre-selected few, and it’s missing a lot of movies in film review aggregator Rotten Tomatoes’s list of best Christmas movies.)