Do WotC have a scrying mirror focused on Leeds DnD? It sure does feel like it.

Last night at the end of the encounter there was an excellent exploratory discussion about teleportation and it limits. Today WotC have posted an article all about teleportation and how it works and it's limitations. This can be read at http://www.wizards.com/dnd/Article.aspx?x=dnd/4dnd/20100713

So leading on from last nights discussion you can teleport a creature into precarious terrain such as lava pits and over cliffs, you can even teleport them into the air only to watch them fall back down again.

However they do get a saving throw and if successful the teleportation fails. Maybe their will was so strong that they were able to overcome the teleportation, or some environmental effect disrupted the spell.

Teleportation does not trigger opportunity actions. Note the distintion there of actions. This includes all types of opportunity actions including opportunity attacks. Teleportation happens so fast you have no time to react to it. Some opportunity actions may specifically target telportation tough so there may be a way to ham string those pesky Teifling's after all.

Another thing of note is that teleportation is not considered to be forced movement.

There are only three types of forced movement; push, pull and slide. I thing the rational behind this is that a push, pull or slide represents a creature moving under their own propulsion as a result of an opponent unbalancing them or guiding them around the battlefield by brute force or a careful combination of footwork, feints and attacks, or even explosions. With teleportation there is no physical movement by the teleporting creature, they blink out of existence an appear almost instantaneously at their destination.