Nope. To my knowledge, IETF doesn't host *any* working group mailing
lists -- they're always hosted by interested members of the community
who donate the resources needed to support said lists. None of these
lists charges a fee to be on the list.
However, since the working group mailing lists are where IETF conducts
its business, it's important that such business be clearly distinguished
from other traffic. An occasional unofficial message of interest to the
group doesn't hurt, but it does hurt to have ongoing discussions which
aren't apropos to the business of the working group. The working group
chairs are expected to keep such discussion to a minimum.
If IBM no longer wishes to support the IPP working group in this
manner, I'm sure we can find another host for the IPP mailing list.
Keith