This was already confirmed 3 or 4 chapters ago when Jiraiya was speaking with Tsunade before he left for the rain village.ZOMG... Much revealed. To those who didnt want to believe it, 4th being Naruto's dad is confirmed.
The translation is kind of vague about this "key" thing. Are they saying the key has the power to reseal the kyuubi and also the power to release it?
Also, I didn't before, but I'm starting to believe the theories now that it was Madara and not Itachi who killed the Uchiha clan. I expect that when Kishi skips over to Sasuke and Itachi in the Uchiha hideout, Itachi will reveal to Sasuke what really happened. Then both will set out to hunt down Madara together. Of course, that's just a wild thought.
I don't believe Shodaime was alive at the time the nine-tails attacked Konoha. Which was why the frog was shocked that Jiraiya would imply that Madara could be behind the summoning. They fought at the founding of Konoha and couldn't have been alive 16 years ago.I guess that's what he was inferring. But Shodaime being able to beat Madara is a bit questionable isn't it? The revived Shodaime that fought the Sandaime along with the Nidaime wasn't all that, though it is a revived corpse. Though, I'm sure it had all his abilities or whatever. Sandaime couldn't touch the Nine-tails when it attacked Konoha, no one could for that matter. That's when the Yondaime sealed the Kyuubi, something so powerful summoned by someone even more powerful/sinister Madara. And the Shodaime beat him?
Either there's a myth discrepancy or it's like a Rock Paper System...