3a. What does 'spam-blocking' or 'address munging' mean?

  (Both terms refer to the same thing - from this point on, the author
  will use the terms 'mung' and 'munging' term to refer to the practice.)

  Address munging is the act of modifying one's email address so that 
  email sent to that address will not be delivered to the person doing
  the modifications.  Typically, this is done in posts to Usenet, in
  order to avoid receiving unsolicited commercial/bulk/boilerplate email
  (UCE/UBE).

  The Jargon File defines 'mung' as `Mash Until No Good', probably
  originating at MIT;  sometime later the recursive acronym `Mung
  Until No Good' became popular.  It means 'to make large changes to
  a file', or 'to destroy data either accidentally or maliciously'.
  It was probably derived from 'munge', which is why you will see both
  words used to describe the practice. Then of course there are the
  Chinese beans.

3b. Munging DOES NOT MEAN MAKING YOURSELF ANONYMOUS

  Trying to hide your identity by faking your email address simply
  does not work;  even an amateur detective can quickly identify the
  source of a message if the From: line is the only thing that's been
  tampered with.  It is possible to be truly anonymous when doing
  almost anything on the Internet, but it takes a lot more work than
  simply changing the From: line.

  Trying to hide from spammers by changing the "name" or "real name" portion
  of your posted address also does not work, because that part of the address
  has nothing to do with email delivery.  In fact, you should make it a point
  *not* to change your "name" if you decide to mung your address.  Many people
  on the Internet have a consistent name or handle by which they become known.
  Changing this part of your identity only makes you unidentifiable to people 
  who have come to know you on the net.