There is two options for www.joost.com to launch a flash movie that works fine on IE explorer and not on Firefox where they push users to signup:
1- Increase conversion rates to their signup funnel with a desperate spirit to attract them.
2- Beeing funny to users with an easy way where your mom, your monky and your moms monky can easily do it. Can you see me now?

Well Done! Joost.com