With Blizzard's World Wide Invitational convention in Paris looming (it's this weekend, 28th and 29th June) the developer is stirring up hype, rumour and speculation with a teaser image on its website.
The image, as it first appeared yesterday, was of an unbroken, craggy sheet of ice. This morning, a crack appeared.
It's undoubtedly teasing a big reveal at the opening ceremony of the WWI, which will take place at 11.45am Paris time (10.45am in the UK) on Saturday morning. Blizzard has not opened a WWI or BlizzCon yet without a major announcement of some kind. The last three brought the first news of StarCraft II and the two World of Warcraft expansions.
The icy theme of the image has led many to suspect that the announcement will relate to the snowbound WOW expansion, Wrath of the Lich King: perhaps a release date, or a significant unannounced feature of some kind.
The many Blizzard fans expecting Diablo III to finally make itself known are not to be discouraged, however. They reckon that the runes just visible in the image, surrounded by circles - as pointed out by Kotaku - resemble the Shael and Hel runes from Diablo II.
Meanwhile, fans at DiabloII.net stumbled upon a work-in-progress personal website for Blizzard artist Peter Lee that featured an empty gallery called 'Hydra' (now removed) and promised to go live on 28th June (now changed to July).
Hydra is thought to be the internal codename for the third game that Blizzard has said it is working on, alongside StarCraft II and WOW. If Peter Lee's site indicates anything, it's that the new game will be made public this weekend.
Eurogamer will be reporting from WWI this weekend, so check back on Saturday to read the news as it breaks. In the meantime, keep an eye on that teaser image for further clues as the week progresses.