Why are some artists successful the first time then ultimately flops after it....
EXAMPLE:
The Black Eyed Peas

(Boom Boom Pow was #18 in the YEC while IGF peaked at around #15 - 17 only yata)
Colbie Caillat

(Bubbly and Realize were more successful than The Little Things and Falling For You which NEVER entered the top ten)
While others are more successful in the second single... Just like Owl City, Secondhand Serenade, Colbie Caillat (Realize >>> Bubbly), etc.

I just wonder...