People have been commenting "off the record" for ages. However, the Internet has made pseudonyms a major meme. Indeed, anonymity on the Internet may be the default choice for the majority of people who venture online.
The obvious problem is that speaking or writing anonymously or pseudonymously could be regarded as inherently dishonest. Part of the problem is a lack of transparency; is the person who's making some political statement on Facebook an authentic activist, a propagandist or a fourteen-year-old troll?
There are, of course, pros and cons to online masquerades. Some can be compared to "little white lies," for example.
Are you aware of any references that do a respectable job of analyzing online anonymity and/or suggesting some guidelines?
I'm also interested in knowing what pre-Internet philosophers had to say about people who broadcast their ideas anonymously. (Were there any notable philosophers who were anonymous themselves?)