Orac can be reached at firstname.lastname@example.org
Note that Orac receives a lot of e-mail. He (usually) reads every single e-mail, but the sheer volume of e-mail that he receives precludes answering everyone. So don’t be offended if he doesn’t respond.
Any e-mail sent to Orac is fair game for publication on Respectful Insolence. If you ask for your e-mail not to be published, Orac will usually honor your request. The exceptions, of course, are if you are a quack, are antivaccine, or are in any way verbally abusive. In those cases, Orac has zero compunction whatsoever about publishing your e-mail. If you threaten to sue Orac, he might even consider it his First Amendment duty to publish your e-mail or cease-and-desist letter for all to mock.