I think I figured out what's going on. Tell me if this sounds plausible. First off, those who say Voldemort is linked to Harry are correct, but how? It has everything to do with how he survived! I’m guessing but how is Voldemort coming back? Simple.
He "stored" a large amount of himself in Harry's Lightning Bolt scar! This is why the scar aches, burns, etc every time Voldemort is feeling something strong, or using magic. What part of himself did he place in the scar? Probably the larger portion of his power! Did you ever wonder why the Wands are the same? Maybe it is because the power is the same! Harry may well have been born a squib!!!! He only has power because Voldemort left him self in the scar and Harry can use all of Voldermorts powers, snake talking, animigus, etc
Dumbledore didn't kill Voldemort because it is useless! As long as Harry is alive he will keep coming back! Voldemort needs Harry to die to release the power and allow him to fully come back! Until then he is a shadow of his former self!
In the end those who say they are setting Harry up for Sacrifice are correct, though he most likely will not have to die. Instead they will have him lose his magic to defeat Voldemort somehow. The precise vehicle for this defeat is unclear to me...

Something else... Has anyone considered that Hedgewig may be a very special owl indeed? We never saw him being "purchased". That task was done out of scene by Haggrid. I've thought for a while that Madam Hooch may be an animagus, and that she may actually be Hedgewig, set by Dumbledore to guard Harry.