Last night, in a moment of (not) irony, the ESRB replied to all of these people without blind-carbon-copying the bunch, revealing the e-mail addresses of these privacy-concerned people for all to see.
The purpose of that email was to inform these concerned citizens that Blizzard had abandoned its plan to force official forum participants to have their real names linked with their posts.
The ESRB has since apologized, placing the blame on "one of [their] employees." The apology has been provided below, via Joystiq.
Yesterday we sent an e-mail to a number of consumers who wrote to us in recent days expressing their concern with respect to Blizzard's Real ID program. Given the large number of messages we received, we decided to respond with a mass e-mail so those who'd written us would receive our response as quickly as possible - rather than responding to each message individually, as is our usual practice. Through an unfortunate error by one of our employees, some recipients were able to see the e-mail addresses of others who wrote on the same issue. Needless to say, it was never our intention to reveal this information and for that we are genuinely sorry. Those who write to ESRB to express their views expect and deserve to have their contact and personal information protected. In this case, we failed to do so and are doing everything we can to ensure it will not happen again in the future.
The fact that our message addressed individuals' concerns with respect to their privacy underscores how truly disappointing a mistake this was on our part. We work with companies to ensure they are handling people's private information with confidentiality, care and respect. It is only right that we set a good example and do no less ourselves.
We sincerely apologize to those who were affected by this error and appreciate their understanding.
Entertainment Software Rating Board
Interestingly, Blizzard's Real ID system has been certified by the ESRB's Privacy Online Program, which focuses on privacy, not anonymity. Ars Technica notes that Blizzard's Real ID program passes the agency's test because it was opt-in, required the registrant to be 18 or older, and fully disclosed what it would collect and do with any personal information.
Real ID will still be an option in-game for StarCraft II, World of Warcraft, and the upcoming Diablo III offering cross-game chat and Facebook integration of some form. It will, however, expose a player's real name to his or her friends and the friends of his or her friends. It is completely optional.