Ok I was under my truck greasing the fittings, and grabbed the tie rod to pull myself forward and it rotated in my hand! It's still attached at both ends, and it doesn't spin freely, but I can turn it without any he-man effort. This movement has also torn the grease boot at the wheel side. What's this about?

Umm, they're supposed to turn... That's how you adjust toe-in. Torn boots can come from any number of things, over-greasing or trail debris, for instance.