The biggest surprise of the decade? Let's not go that far, Russo.
The decade is only six years old and no one outside of a few people in TNA had any IDEA it was happening. TNA screws up a lot of things, but they did manage to make one amazing surprise since there was absolutely zero spoiler about it. Which considering where we are at in the time of wrestling is beyond a surprise, it's damn near improbable that they actually kept it secret.
I agree, in this day in age, its so difficult to keep something a secret in wrestling these days. What with Meltzer and all of the other "insiders" giving away spoilers.
But TNA and Dixie kept sigining Angle a secret, and very well i might add. No one saw it coming. People speculated, but no one knew he was signing, unlike some of the other aqustiotions like Christian, Rhino and Team 3D.