Blizzard has not announced any plans to include in-game advertising in Diablo III. There are no in-game ads in World of Warcraft or Starcraft II, so it seems unlikely that they'd start with Diablo III. After all, nothing in Diablo III's fantasy world supports advertising.
If Blizzard were making a sports game or a racing game, then ads on the cars or around the stadium would be necessary for realism, but they haven't fit into any Blizzard games so far.
Players will see ads when they log onto Battle.net, for multiplayer Diablo III, but none in the actual game, and Blizzard has never (yet) included ads in their loading screens or along the browser bar in the game, etc.
Bobby Kotick on In-Game Ads
Bobby Kotick, CEO of Activision/Blizzard and (fan-alleged) source of most of the corporate/capitalistic evils that intrude into Blizzard's games and Battle.net, said in September 2010 that they had no plans to force ads into more games.[1]
- “There was a time where we thought advertising and sponsorship was a big opportunity, but what we realized is our customers are paying $60 for a game or paying a monthly subscription fee and they don’t really want to be barraged with sponsorship or advertising,” Kotick said. “So being very respectful of our audiences, unless it’s something that’s really authentic and will enhance the game experience, we’re generally not going to include something in the game.”
- “There may be future opportunities where you might offer a consumer an advertiser-supported experience so they wouldn’t have to pay for it,” he continued. “But as long as our audience is paying $60 for a game or a subscription fee I think we’re going to limit the amount of advertising or sponsorship incorporated into a game.”