I am trying to understand this macro.

[Phanes]

/clearfocus
/focus [target=toon1, exists, nodead][target=toon2, exists, nodead][target=toon3, exists, nodead][target=toon4, exists, nodead][target=toon5, exists, nodead]

Ok so this macro sets the focus to toon1, toon2 etc etc

So what does setting focus do?

Probably a better question is how does this help?

Do you /assist or /follow after you set focus so with this macro if your team gets split up they can follow or assist eachother? Or if someone dies they will just start assisting off toon2 etc?

[alcattle]

quick way to set focus when used with the boxing macro so hit 2 keys and you are set.
From Macros for Beginners Sticky

******  This is what I call the "Big Button".  I hit this a lot:

/target focus
/follow
/assist
/stopcasting

As you can see, this macro targets your focus, follows him, assists him, and then does a stopcast. I hit this ALL the time to make sure my guys are following, assisting (latency sometimes screws up assisting if you just use it in conjunction with your spell you are casting), or if I want the group to stop casting.