This article What's In A Name at Design Observer, Steven Heller argues against the use of pseudonyms and anonymity in blogs. He states, but never really argues, that pseudonyms are:

Cowardly
Deceitful
Unacceptable

Despite the fact that I blog under my real name, few may find it surprising that I disagree with his claims. In this age where every word we post will last well beyond our years on earth, one should take great care about posting anything under a real name. I hold very different opinions now than I did when I was young. I would not want to have those thoughts thrown back in my face. Many bloggers hold opinions that run counter to those of their employers. Making strong arguments that might be detrimental to ones employer could well be a "career limiting move". The fear of such retaliation is often much worse than the reality. The chilling effect on speech can be significant. Far from being cowardly, I argue that pseudonymous blogging is simply prudent in many cases.That pseudonyms are deceitful would seem to apply to only a very small subset of bloggers, those who are using a pseudonym that appears to be real but is not and which is masking a true identity that, if known, would significantly color a readers interpretation of the blog. In other words, where the choice of the pseudonyms is made with an intent to deceive. The vast majority of pseudonyms I have seen used are obviously such. There is no doubt that the author is using a pseudonym. The desire to speak from behind a mask is completely overt. In addition to security and privacy concerns, one may well choose to do this to allow the writing and arguments to stand on their own, completely apart from the identity of the writer. For example, in a forum on Israeli / Palestinian issues, the ethnicity of a posters name is likely to completely overshadow the content of the message. A pseudonym allows the reputation of the blogger to be developed on its own. If the arguments and information are sound, the reputation with grow. Because names are not unique identifiers, the use of a real name (or apparently real name) in a blog may give an unrealistic sense of attribution.I completely support the right of people to create spaces where people must be identified. It is their right to do so, and is completely appropriate and reasonable. It is unreasonable and inappropriate to suggest that this should be imposed on the entire Internet and all communications therein.