Imagine a person who comments regularly on certain blogs under a pseudonym, and writes her own blog under a different pseudonym, and then of course "IRL" or "offline" has an official legal name. Not an especially unusual situation, I imagine, and one that few of us would find upsetting or even noteworthy. What if she told one group of friends that her name is Carol Watson and another that it is Tamar Weinberg, while at work and to her family she's known as Jennifer Esposito? Do we have a problem with that? My sense is that most of us would find that kind of creepy – even those of us who find the use of various online names perfectly acceptable. But why? If it's okay online why wouldn't it be okay offline?
… I'm not sure precisely what Alexis has in mind here, but our public identities are attached to a lot of what we do everyday: not just our written and oral exchanges with friends and co-workers, but most of our purchases now that we increasingly use cards rather than cash. More than at any point in human history, the average person's everyday life is made up of statements and actions that are "public, persistent, and attached to [his or her] real identity." So in that sense our expectations for online conversation are outliers.