According to Gaon, "Shy Boy" has sold over 2,215,864 digital downloads in South Korea as of December 31, 2011.

In South Korea, "Shy Boy" entered the Gaon Single Charts at number 18 during the week of January 8, 2011.

In a year-end chart by Olleh Music, "Shy Boy" ranked at number 5 for best selling and most streamed songs for the year.

Directed by Johnny Bro's Hong Wonki, the music video was released on January 6, 2011.

The video has a "swing dance concept" with outfits, hairstyles and sets that draws inspirations from the American culture in 1950s.