With Marvel Heroes, which has been described as "Diablo with superheroes" and even has the team behind the first 2 Diablo games working on it. The MH team enjoys taking lighthearted jabs at Diablo 3 in some updates and notes.
Fan Nickname: Leablo: The Diablo-possessed Leah at the start of Act IV.
Flip Flop of God: Is the male Barbarian the same one from Diablo II or not? Some Blizzard employees say yes, others say no. As of the official release, it was finally decided he isn't.
Internet Backlash: As of August 2013, Diablo III holds a 3.8 from Metacritic users (including over 1000 negative reviews) for the massive lag spikes for being forced to play online at all times, reduced content (like PvP) that were in the prequel and Error 37 (inability to connect to the game).
Schedule Slip: All Blizzard products have a release time of "Soon" (TM). This game began development in 2001 shortly after the release of the Diablo II expansion pack. It would be eleven years before it would finally release. It wasn't officially announced until 2008, and then didn't hit beta until 2011, before finally releasing in 2012.
Sequel Gap: Diablo II (2000) and Diablo III (2012) — 12 years.
Trolling Creator: Blizzard had to put up with constant complaints about how "cartoony" and "colorful" Diablo III is compared to its predecessors. As a pisstake to that section of the fanbase, they put this level into the game.
As part of the 2009 April Fools' reveal of the "archivist" class (a librarian), Blizzard released a mockup of the radial dialogue tree players could use to navigate conversations. Among the cantankerous things the archivist could say was "In my day, there were no colors."
These are the people who date their releases and patches as either "Soon" "Very Soon" or "Soonish", all of which they define as any time between now and the end of time with Very soon being most likely to be closer to now and Soonish to be closer to said end of time.
Urban Legend of Zelda: The official site, specifically, the home page, has its own chat gem. After a massive thread on the Battle.net forums discussing whether clicking the gem a certain number of times would unlock the playable version of the gameplay demo seen when the game was released (started by a forum troll and helped by various random people confirming it), the matter was laid to rest when someone looked in the source code of the site, decompiled the flash that operated the chat gem, and determined that its only purpose was to change colors, changing the gem from "on" to "off".
The Male Barbarian was supposed to be the same guy from 2, but this idea was scrapped by Blizzard, possibly because if it was the same guy he'd be 30 years older, and they would have to explain why the game doesn't start him out at level 40+ and fully decked out with high level magical gear.
A number of features that were mentioned in demo videos never materialized in the game, such as obstacles that required certain class abilities to navigate, in-game cinematics, additional NPC allies, as well as entire dungeons.