I've just finished a few tests on threat generation with a young druid (14) assisted by an even younger hunter (5, thanks Pook) against level 5-7 foes. I then quickly checked a couple of interesting results with my main (52 druid) and a 13 warrior against level 13-15 foes (level ranges chosen so that I didn't have to worry about dying while testing and could easily protect my partner once the foe turned on them; I'd have preffered a 30-40 warrior for the second tests but the 13 was available and interested). All numbers are rubbery as I haven't spent a lot of time on this - consider them to be indicators, not proof. Lots more to investigate, but here is what I have so far:

For a Hunter's default melee to pull something off me he needed to do about 50% more damage than my bear form autoattack. I could pull them off him at roughly par.

To pull off me in caster form after I'd used spells he needed about the same damage as my spell. I only tested this with Wrath.

Healing spells generate threat proportional to the amount healed, not the number of casts or the level of the spell. Point for point healing generates less threat than damage - I estimate that I needed a little under two points of healing to pull a foe for each point of damage my partner did. Overhealing does not generate threat (I couldn't pull a wolf off my partner by wasting my highest healing touch to heal a sliver of damage; against a new foe I could pull with a single cast (after they stopped attacking and waited for enough damage that I could heal almost their entire bar). This was largely using Healing Touch, with only a couple of Regrowths and Rejuvenation cast because the HOTs are harder to track total healed with.

Demoralising Roar (a 34 attack power debuff) generates threat equivalent to around 8 to 10 points of bear damage; this does stack with repeated casts. That puts it somewhat behind Maul as a threat generator against single targets in terms of threat per rage, but superior aginst groups. The talent does not appear to increase the threat this skill causes - which is a bit disappointing as I'd hoped the talent might be useful for something
Testing the effect of this talent is the reason I ran a new Druid up to 14 (that and wanting to try a pure tank build with the class). The higher level debuff on my main seems to generate threat in about the same ratio (~35 damage worth of threat from a 130 debuff).

Enrage generates substantial threat - in several cases enrage alone was enough for the creature to die before it could be pulled off me. This threat appears to be per tick, not all generated on the initial cast. I'm not sure whether it scales with level, doing a brief check with my main (52 Druid) and a teens warrior the warrior could pull things off me in a few swings if all I did was enrage.

Thorns appears to generate threat normally (proportional to the damage it does). I'm unclear as to whether the bear threat bonus applies - results here were inconclusive.

I dearly wish the threat generation of various skills was better documented, it being such an important part of party play.

Interesting findings.

It's always been argued whether or not successive demoralizing shouts/roars stacked, so it's good to know that in your findings they do.

This is some great stuff Warlock. If you are on Proudmoore I'd be happy to do some more of this with you. I have a high level druid there.

I had never noticed the large threat generation from enrage, but I use it sparingly. I'm going to have to play with this. One thing I didn't see in your post was swipe. In my experience this seems to generate much more threat than the damage would suggest. I use it a fair bit when tanking to try and hold 3 or more mobs.

-DarkCrown

I'm Unity on Eonar, I just accepted the server suggestion, it was lowest pop when I first joined. My latency is bad enough already (I'm in Australia) that I don't really want to try a higher pop server.

I just assumed that swipe created threat normally, I'll have to test this now
I used to use swipe constantly when tanking but have largely switched to demoralising roar now - it's crowd control friendly, isn't limited to three targets and has a decent radius. Just don't use it in a room full of yellow foes!

One of the priest threads on the blizzard board contains some excellent threat data - including a claim that health/mana potions create threat. I'll check this soon. If so I would guess that rage potions and thistle tea also do this.

Swipe has issues for sure. If there's more than three mobs in front of me I change targets and reswipe. This sometimes lets me hit a new mob and hold aggro on more than three. Hitting sheep with this trick can be a real problem.

As far as servers go, Proudmoore has a huge Australlian population, and they seem to have no trouble playing. The Older Gamers (a mostly Australian gaming site) has several guilds on the server (for the over 25 crowd) and has been a great gaming experience for me.

-DarkCrown

Ok, I'll keep Proudmoore in mind for my next alt.