Yes. You need to do the exploit every time you start your ps3.
No, not that I'm aware of.
Don't click on it. No need to.
Yes, you can use an AT90USBKEY. No, don't go online at all if you don't want to be banned.
Yes, it 100% works on teensy board. People who aren't able to backup onto their internal drives are trying to use one of those "Stealthed" backup managers, that aren't actually stealthed anyway. If they use the original they'd be fine.