This is how Wizards of the Coast leaked the card Jace, the Mindsculptor to the world.
As written on the Wizards of the Coast website:
“A Planeswalker has escaped from Worldwake and we need your help!
This Planeswalker has left clues scattered all around Earth – Our Plane –in the form of of a Planeswalker card from Worlwake hidden in eight different locations. Beginning Monday, December 14th, 2010 and continuing for four days, Wizards of the Coast will post the latitude and longitude of two of the pieces each day. You are encouraged to seek out the piece of the card and participate in the global jigsaw puzzle to put the card back together. With all your help we can track down this Planeswalker.
Check the Wizard site each day starting Monday, December 14th and see if that day’s pieces might be hidden in your neighborhood.”