Twitter user
Phenom has a theory that it corresponds to hieroglyphics of parchment, that if tallied and grouped together form this set of numbers: 9, 17, 12.
Obviously, that could be a date: September 9th, 2012.
Twitter user and Mentors Guild member
Turul has also suggested that this date could refer to the day that Desmond, Lucy and the gang arrived at the Auditora Villa sanctuary.
If you want to really put your tinfoil hat on, there's also a theory that this date could be important because assuming Layla can alter time itself, this could be a point to save Desmond and Lucy while stopping Juno entirely.
But that's a huge reach. Still, it would be really interesting!