Total noob question about FOKFollow

Just hit 80 last night, so the concept of FOK is still new to me. Can someone tell me at what point I should be using FOK instead of targeting my dps on a single mob? I was told the time to use FOK is when there are 3 mobs or more.

Can someone confirm this?

The use of FoK is completely up to you. There is no reason to use it on pulls less than three mobs though.

I normally target one mob and ss to get two combo points, and put up a SnD on that mob. Then, I just spam FoK until the mobs are down.

I know a rogue who takes the Imp Thrown weapons as filler points instead of endurance. When he pvps he uses FoK as an AoE type silence.

I've evasion-FoK aoe'd mobs before during dailies, like the mammoth packs around the ooze cave, just to see if I could. Outside of a raid aoe pull setting or pulling rogues out of stealth after they vanish, it doesn't have much practical use.