Update: Diablo 3 has been confirmed! Check out this announcement!
So far three runes have been presented by Blizzard and the ice is gradually breaking, raising even more speculation about what this all means. The first one belongs on Arthas' runeblade, the second is the sign of the Protoss while the latest appears to be the Hel Rune from Diablo 2 so everyone is very anxious to see what announcement will be made next this weekend's Worldwide Invitational event.
With this last rune, the Diablo enthusiasts have their morale boosted once more and the Diablo 3 rumors intensify, but so far nothing is certain and we'll have to wait until Saturday to see which is the next surprise Billzard is preparing for their dedicated fans.
UPDATE - Day 4
The forth rune has now appeared on the official Blizzard page. Speculation continues amongst fans and gaming sites. Ice is melting slowly and you can almost see some glowing eyes.
While it can still be almost anything, a clever forum poster has just added a Diablo II cover on top of this splash image and the result are interesting.
Another interesting aspect is the html source code, containing some strange lines like colors #040404 and #060606 (both shades of black, so probably the numbers are relevant); plus the text "get ready".
Update - Day 5
With less than 24 hours before the moment Blizzard will finally make the announce about the mysterious image captured in ice, speculation continues amongst fans and gaming sites. The games editors from Games32 came with the idea that those glowing eyes might belong to a Protoss unit; adding a Starcraft picture on the top of the splash image has a very interesting result, as you may see here:
Final update
We're talking indeed about Diablo 3, which has been announced officially today, June 28, 2008 at the Blizzard Worldwide Invitational in Paris. This is the launch announcement.