With the Blizzard World Wide Invitational only a few days away, Blizzard beyond all expectations updated a teaser on the official website with the below image. ( Relevant: Blizzard Hints at New Game? )

( The image is named "Ice1.jpg", there will probably be more icy images to come.)
It is unclear yet what the image means, but many players analyzed it may a signal about the release of Diablo 3.
With many puzzles, the splash screen at Blizzard has changed slightly. The crack in the centre has become larger so more light now pours through but more interestingly.

(The splash page teaser has been updated around 12:10 am.
A new symbol appeared on the upper-right side of the ice fissure.)
This image from the splash image teaser resembles the Diablo 2 semi-rare gem: Hel Rune.

With this splash, the website of blizzplanet pointed out a pattern on the master.CSS file. It said that yesterday the name was Tundra and the name of the sencond splash is Cavern. The pattern points toward one of the Diablo Acts' locations.
However, the splash image isn't stop to be updated yet. The third splash image came to us now.

(A few new updates: The master.CSS file added the word: Icy.)
The new splash teaser shows clearly that the ice is melting. On the lower left of the center there is a new rune inside a circle. This is the Akilae Tribe symbol in Starcraft 2.

According to forsinain and DeepFreez from the diablofans forums, now the three words on the CSS file are: Tundra, Cavern, Icy. Frozen Tundra, Drifter Cavern and Icy Cellar. All names could still be referring to Act5 areas. Icy cellar is the second area that you can access from the Ancients' Way (the first being the Summit)
What is the real meaning of these images? Rob Pardo said at the GDC: "So you want me to announce the game before our announcement?" he said. "No offense, but I think there's like 300 people here, and I'll be ripped apart by 8000 people there [at the Invitational] if I pre-announce it, but it's going to be really exciting. I think everybody here will be really excited about the announcement."
This time, what joyful surprises you will experience? Please stay tuned, we'll let you know if we find any additional information regarding this matter.
[Editor:Stella]