This page will collect and collate arguments for and against online
pseudonymity, the practice of posting views under a persona named
differently from one's identity in other parts of life.  (I acknowledge
but will not delve into adjoining issues like: What exactly is a "real
name"?  Can't one have multiple "real names"?)  

The term "pseudonymity" was coined in contrast to anonymity, to
acknowledge that many such identities have a long-term stability with
attached credibility.


Reasons Why Pseudonymity Is a Good Thing:
Foiling stalkers
Removing one's sex or ethnicity from the discussion
Whistleblowing
People living under repressive political regimes.
People getting fired because of their blogs (Heather dooce.com and The
Sarcastic Journalist)
"Handles" sometimes are more reliable than real names -- in in some
senses more real.  (It's not unknown for a "real name" to change
multiple times in a decade over which the corresponding "handle" 
remains unchanged.  Also, some "real names" are so common that those
persons' handles may be much more identifying, in practice.)
Ultimately, what defines "real" in a name is consistency and willingness
to stand behind it, as opposed to "nonce pseudonyms".
Avoiding prejudice in professional life against one's religion / hobbies
/ pastimes (Wiccans, furries).
Some "handles" lend amusement and a sense of fun
Shouldn't the merits of one's arguments stand on their own?
The ability to define who one is should be respected, not denigrated.
How do you know a "real name" is real, anyway?
How can you be sure someone posting from a "real name" isn't an imposter?
Protection of children when they're online.


Reasons Why Pseudonymity Is a Bad Thing:
Sock-puppeting / drive-by rhetoric
Ballot-stuffing
Fraud / impersonation
Libel
Rumour-mongering
Other crimes/misbehaviour and other irresponsibility from 
behind cover of near-anonymity and lack of accountability.
People who want to be taken seriously in general _don't_ hide who they are.
  Standing behind what you write is a mark of integrity.
Ever been stalked / threatened by pseudonymous people?
http://www.kathryncramer.com/wblog/archives/2004_04.html
Some posting under a real name who allows himself/herself to 
  get drawn into debates with "handles" stakes his/her established real 
  reputation against those of basically fake, invented people.  See:
  http://jroller.com/page/pyrasun/20040517#the_anonymous_fakers



Some pseudonymity is accidental, e.g., AOL and other technopeasant users
of e-mail who fail to define realname (GECOS) fields and then post or
mail opinions without realising they're posting namelessly.