I'm pretty happy to see this happening now, because clearly it's a ramp-up of the viral marketing for the new Half Life 2 episode.

They hinted in the last episode, and in Portal, that something would happen to link the two games. Some of the images confirm this, showing that the "Borealis" ship (shown at the end of the last half life game) contains bits of technology that we saw in the Portal game.

The obvious prediction is that, in the next Half Life episode, we'll get to use the portal gun as a weapon against the Combine. My guess is that a significant portion of the game will be attempting to get to the Borealis and retrieve the technology; we'll only get to actually use the portal gun as a weapon in the set-piece finale. But that's just my guess.

In any case, I'm very excited because this means that, at least internally, they're counting down to a release.