I don't know why IPC chose to use an email forum but I for one am glad they did
because at my facility we can only readily use email on Internet at present and I couldn't participate otherwise; it allows me to read or delete email comments as my time allows; and if I'm working at some weird hour jamming out a pcb and
want to send out a comment it doesn't matter if everyone else is home asleep-
they'll still get my query or comment at the right time for them. These IPC 
email forums are great. We recently recommended to our CAD software vendor
that they set up a forum modeled after these for their users and they agreed.
It's really helpful and somewhat reassuring to have my peers available at my 
fingertips 24 hours a day, seven days a week!! Thanks IPC!