Halo 3: ODST was one of Bungie's last games before separating from Microsoft to work on its next universe. Apparently, the company knew what it was planning for the future well in advance--so much so that it sneaked an easter egg into the now-three year old game.
A Kotaku reader discovered a poster in ODST that promises "Destiny Awaits." It shows an unassuming planet with a small white moon, just like in the leaked documents that recently made the rounds. A tweet from Halo level artist Vic Deleon confirmed the connection.
It stands to reason that the white moon in this poster could be the snow-covered area from the game's recently-released media, but we'll have to wait for more information from Bungie. Or another easter egg. Quick, someone boot up Marathon!