This is and example of an interactive Advert.
Firstly, having a finger and arrow on the screen picked my curiosity. Then the guy starts talking about everything that will happen to my finger and this post I was to curious to not put my finger on the screen.
I don't know if makes you buy a skittle but putting your finger on it it elicits a feeling. You might feel happy, find it funny, be perplexed about why you feel that way or even feel ridiculous about it but you associate an emotional or mental reaction to the ad if you interacted with it and it makes it a bit more memorable. For this ad I felt a bit ridiculous and every time i thought about how I felt over the next few hours, I remembered/ thought of a skittle.
While this Ad might not work for everyone, the introduction alone increases the likelihood of an interaction