Well, I'll be—you're absolutely right! How did I not notice this before?

    Cupcake (1.5)
    Donut (1.6)
    Eclair (2.0–2.1)
    Froyo (2.2–2.2.3)
    Gingerbread (2.3–2.3.7)
    Honeycomb (3.0–3.2.6)
    Ice Cream Sandwich (4.0–4.0.4)
    Jelly Bean (4.1–4.3)
    KitKat (4.4)

Toast notifications are those little gray popups available to developers in the Android OS