I guess that applies to stealth as well? Because I had a thing with stealth out and they could attack it with "special" abilities. Would be nice if they were clear about this.
Eh, its not all that hard to understand. There are attacks, spells, and abilities. Attacks are when one player specifically chooses to use the default attack of one of their minions (or their hero, if they have a weapon). Spells are cards that say 'Spell' along the bottom of them when you mouseover. Abilities include hero abilities, and generally any other effect in the game, such as battlecry's. There are a few other 'effects' in the game that aren't really covered by these three, but keeping the above distinctions in mind should clear up most of your confusion.
Now, if you look at the description of taunt in game, it says:
"Enemies must
attack minions that have taunt."
In other words, it affects only attacks. Spells and abilities are not affected.
The in game description for stealth:
"Can't be
attacked or
targeted until it deals damage."
So with stealth, not only can you not be hit by default attacks, but a stealth minion can't be targeted at all while it remains in stealth. It could, however, be hit by a spell or ability that does not require targeting, aka any AOE ability (such as flamestrike).
Things can become a bit murky when you start looking at how things work when you combine multiple minion characteristics, spells, abilities, and some of the unique effects into one interaction. But again, keep in mind the difference between an attack, a spell, and an ability, and carefully read the descriptions, and you should be able to figure it out 90% of the time.