In Digital Marketing that is a strategy called social proof, which is used to show to customers that your product is well received by the general public.

Selfzapping could create an artificial social proof that your post is relevant. "That many zaps? The community clearly thinks this is good."

Social proof works. You are more likely to zap a popular post - a.k.a. a post that was zapped a lot - even after knowing what social proof is.