Basically, Sneak does two things - depending where you are in relation to the mob. One, automatically sets you to indifferent if in the rear arc of the mob - and two, reduces aggro range if in the forward arc of the mob.

If you come up behind two mobs and fire a bow, or throw at one - only the target will come as long as you keep sneak engaged. It negates him from chain aggroing the second mob. As if the first mob normally says "Come on, there's a guy over here" and the second says "I don't see anything", shrugs and stays where he is.

There are some mobs that work on social aggro that don't need to "see" the player to be aggro'd by the other mob, most of the time sneak pulling won't help in these isolated instances. But there are LOTS of mobs people have told me are linked by social aggro and I couldn't sneak pull just one, yet I have *shrug*

Anyways, most mobs in norrath work on chain aggro - one runs by aggro'd, it aggro's another, BUT Sneak negates this in most instances.

Sneak pulling can be done from in front too, but requires greater range. Throwing will not work from in front....you can be in front of the target, but NOT in front of the additional mobs you don't want to come. Throwing requires you to be too close to be out of aggro range when hide drops, even with sneak engaged. A nice bow with good range works well for this. If you are far enough away, with sneak engaged, you can fire at one, and the other won't come, even if facing you.

The important thing is KEEP SNEAK ENGAGED until the mob is past anything else it can aggro on it's way to you. If you get hit so that sneak is off, or just take it off, then all normal chain aggro comes into effect.

By the way, because of this, sneak pulling casters is trickier. If they hit you with a nuke, sneak comes off, re-engage it quickly and you have a chance still to negate any chain aggro.

In the end, it's all in the placement of the mobs, use angles and line of sight to minimize aggro with the others you don't want. It's not a simple case of "put sneak on, stand in front of two mobs, hit one and the other shouldn't come". There is no substitute for experience, pathing and aggro is different everywhere. Learn exactly how sneak affects/reduces that aggro in different places and then put it to use.

Responses to some questions:

Yes, aggro radius pulling is useful with sneak too. I use this in Karmors basement where the halls are narrow an there is no room for range weapons.

Line of sight helps a lot in these cases. If you get in a position where one can see you but another can't, while having sneak and hide engaged, then you drop hide - but keep sneak on.

Soon as you see one start to aggro and move, back away quickly. As long as you are out of aggro radius of the other by the time it hits you and sneak drops, you only get the one.

Using this, I have been able to keep the basement completely cleared, getting nothing but single pulls for 8 hours. It makes having the "necessary" cleric and chanter unecessary in an area that gives great xp - I've done the whole basement with nothing but 2 rogues and a druid.

As for Hide, it doesn't really affect the chain aggro betwen mobs - Sneak takes care of this. The usefullness of Hide only comes into play if you have to pass other mobs on your way back to the group with your pull.

If you are hidden, you can pass other mobs safely without aggroing even though your pull is aggro and following you.