You can react to Pins to share your opinion and give feedback to the person who created that Pin. Reactions are available for video and Story Pins only at this time. You cannot react to video ads or promoted video content.
You can react to a Pin in different ways:
Reacting to a Pin shares your thoughts about it, but does not save the Pin. If you want to see the Pin later, make sure to save it to a board. You can also click on the number of reactions on a Pin and see who reacted to it.