Update: Added Jay Wilson's reply on Twitter.
Official Blizzard Quote:
can you debunk the rumor of april 17th or confirm?
I cannot debunk or confirm.
Diablo 3 - Release Date Rumor: April 17th
We are getting a lot of PMs about a leak from an Italian website and at this point it's probably worth mentioning on the front page. A site named mmorpgitalia.it supposedly received information saying that Diablo 3 will be released on April 17.
Even if this news comes with the price structure for the regular and collector editions of the game, it still seems very strange that only one website got the news. Also keep in mind, Blizzard said they would like to give us a two month window before the game is released. This date would only give a little over a month window.
Amazon also reflected the change of date on their italian website but at this time, it's still a very much unconfirmed rumor and it should not be taken as fact yet. Feel free to use this news post to consolidate all discussions about it, and keep in mind that this is probably the 20th rumor we have seen about a release date. The only difference is that Jay Wilson confirmed that an announcement will happen soon.
Quote from(Google Translation)
Activision has revealed Italy to several large retailers Italian release date, some yet to be confirmed at the world average by Blizzard but rather than trust, of Diablo III . This would be the April 17, and prices are now set at € 54.90 for the standard edition and € 89.90 for the Collector.
Since the source is the Italian branch of the same publisher, I would say that after Easter to all the fans who are eagerly awaiting the release of the game will be more than positive. The rest of the dungeon crawler par excellence is almost ready for some time, and the latest statements have been conducted to art to increase even more hype.