I'm not going to embed the video, I have limited bandwidth. But you can access the video in Quicktime and WMV formats here. And you can bet that the whole of the Mr. Bush's Internets are abuzz with what this teaser trailer is supposed to mean. Though that would take some insight from people who have actually read the five books that give more meaning to the Halo Universe. Luckily for me; I have.
From the Keep it Clean and Pardon our Dust transmissions from the planet's Superintendent. It would appear that the following game or content will be taking place slightly after the start of Halo 2 and before the events of Halo 3. Where a Series I Spartan (there could possibly be more) will lead a massive force of ODST's (Orbital Drop Shock Troopers) to take back the New Mombasa after the slipspace escape of the Prophet of Regret during the events of Halo 2.
The Proof is in the Pudding. SPOILERS AHEAD!!! You've been warned!
Halo 3 and many of it's overtones were reflections of the books. References to glassing planets, shield worlds, and the massive Forerunner bots leaping to another planet were all events that correlate to the book: Ghosts of Onyx. Where Jon's (known to many as the Master Chief) Blue Team is trapped inside a Dyson Sphere with a team of SIII, or Series III Spartans, and the Spartan program founder Dr. Catherine Halsey.
While Bungie dev's and Microsoft have always said that the books were always intended to develop the mythos of the Halo Universe. It's becoming more clear that they intend to tie the two together. Even if that means coming up with alternate time lines or better explanations of why Blue Team never made an appearance in Halo 2, yet were in direct contact with Jon in what could be seen as a prequel to that game in the book: First Strike.
First, take a look at the Keep it Clean transmission. This is a record of the Office of Naval Intelligence or ONI, where a Communications officer is trying to get in contact with his C/O. ONI is the UNSC's answers to our modern day CIA/NSA intelligence community. They are the home of the darkest secrets within the UNSC and the breeding grounds for the Artificial Intelligence and Spartan programs.
Then take a look at the Pardon our Dust transmission, which is clearly depiction a C/O of the heavy cruiser "Say My Name" approving a request from a Captain for troops that will no longer report to Fleet Command. The Captain is using the transmission code "DARE.V.500341(S1)." Where Dare is his last name, V. is his first initial, the number his registration, and the S1 for Series 1 Spartan. And Spartans only report to ONI officers and UNSC Admirals "in the know."
Those who have read the books know that the S1 Spartan's have only been referred to as a "massive failure." And approximately only a third of the soldiers that went through the SII program were combat functional after implants and surgeries. This might explain why there may only a few of these S1 Spartan's left, and why they have been a relative no show within the books though many speculate that Chief Mendez, Jon's first C/O, was another likely candidate as a S1 Spartan.
What ties my hypothesis together is the fact that the teaser trailer reveals the white light emitted from The Prophet of Regret's ship when it left New Mombasa for installation 05. Now Earth has been infected by The Flood (Halo 3) and New Mombasa is one of the last unglassed habitable places on Earth. Moreover, New Mombasa was where Blue Team was fighting before they made the jump to Onyx, and it was also the starting point for the game Halo 2.
After being blown apart from the slipspace New Mombasa is host The Flood, it will be up to every soldier within the UNSC force to be called into action; even the surviving first generation of Spartan's.
In the end this will only be a taste of what's to come. My guess is that the DLC will be only a few levels of what may be a new spin of a gritty tactical shooter based within the Halo Universe. What many have known as "Halo Blue," which was slated to release September 30th 2008. Many fans of the books have always asked for games that have been more representative of the accompanying literature. But considering that the the three games have eluded to the fact that Jon is the last Spartan left. This new addition may blow all the holes in that theory for those who haven't read the books and finally tie the two mediums together.
Granted my theory has holes and the teaser trailer doesn't due enough to suggest what the new DLC will be exactly. But this is Bungie, they always play it close to the vest. My guess is an educated one and if I'm not right I'm damn close.