Update - Microsoft has issued a statement to Polygon saying that the page promising pre-loading "was posted in error" and apologizing for the confusion. "However, pre-purchase and pre-download for Titanfall for Xbox One will not be available from Xbox Store," it stated. "We'll continue to strike a balance between digital distribution and its benefits, while supporting physical games purchase through our retail partners."
Original Story - When Titanfall launches next month, you'll be able to skip the wait time of buying it at a store or downloading it from the digital shop. Microsoft revealed today that you'll be able to pre-load the game on Xbox One, letting you jump right into a match at 12:01 AM on release day.
The Xbox Store page puts it plainly: "Xbox One game expected to release on March 11th, 2014. You may download the game from Xbox Live before then, but it will not be playable until after 12:01 AM PST on the release date in your country." The page also shows the installation as almost 16 GB, so depending on your connection speed the download may take a while.
This functionality only applies to the digital version, obviously, and you have to pre-purchase it and be charged the full price now instead of later. But if you're itching to play at the very earliest moment possible, that would seem to be the best route.