MMORPG.com linked to an article over on Gateworld.net (so, it must be true!) saying

Gateworld.net has announced that when Stargate Atlantis returns to Sci-Fi on January 4th, they will be showing a trailer for Stargate Worlds.

Further to that, the Jan. 11th episode of the show will kick off a new SGW promotion.

See the MMORPG.com news posting.

And over on the Gateworld.net news article that they linked to, it says

…make sure to tune in to Atlantis when it returns from the holiday break on January 4. That night will feature the first look at the Stargate Worlds game trailer.

So, now we know why the main splash page for SGW has been updated!