I think the purpose of each mailing list should be determined by that
 list's owner(s) with input from whatever sources the owners care to
 take into consideration.  So, the question "Are anonymous postings
 appropriate?" is only answerable (in my mind at least) in the context
 of a specific list.  Each list owner has to answer that question for
 themself and their own list.  In other words, I don't think there's
 much utility in trying to decide the point for anyone else.  Both
 Geert Marien and Paul Graham are free to make their own decisions
 on the matter, and don't need to consider anyone else's opinions in
 doing so.
 
 For those who would like to prevent anonymous postings, please note
 that it's virtually impossible to do so.  My guess is that if it's
 really that important to only have postings on the list from known
 sources, you're best it so create a controlled subscription list
 where only the list members can submit messages.  And even so, it's
 no guarantee that people won't spoof you despite those roadblocks.
 
 -jj