Wikipedia article about this topic .Taylor and Jaime King did the "ALS Ice Bucket Challenge" to raise money for ALS research.
List of those who participated at Cultural Phenomenons. 
Taylor Swift uploaded a YouTube video of her doing this with others on October 6, 2014.
As a tradition, they thanked those who challenged them, Ingrid Michaelson and Lily Aldridge, and mentioned the people they challenged in return. Taylor nominated Selena Gomez, Emma Stone, and Ed Sheeran. She held a handful of cash showing she was also donating money to the cause.
Selena Gomez has thanked Taylor for the challenge and accepted, having cold water dumped on her head.