I have no background and already dropped out of a Chinese class back in college. Since "discovering" Popup Chinese, I've learned more Chinese, learned faster, and had way more fun learning than I ever thought possible.... I listen so much so often that I can recite some episodes by heart and mimic the voice actor/actress by now (I'm still at the Elementary but these days I can somewhat follow along TV shows and radio, which before only sounded like an incomprehensible jumble of sound).
With the success from listening/speaking, I've even feel encouraged enough to venture into learning Hanzi (and learned enough to stalk my friends' Facebook status and read some simple writings). When my friends compliment my Chinese, I proudly tell them: 四個字：泡泡中文!