Is the use of an Assumed or Fake Name illegal?

Well, if it is then most of the Internet usage is a perpetuation of this criminal act!

I (my real name is irrelevant), like so many others, have used a pseudonym or alias in many of my Internet dealings. In fact it is a well established technique to protect the spread of personal information where you do not wish to have that information publically shared. The use of such a pseudonym or alias should not be seen as anything sinister or underhand.