the yahoo or google group is fine with me.
I wasn't asking that you do this, but just offering it as an alternative, since you and others seem to be having trouble with yahoo and google.
of course, a regular forum is nicer, and this is what people are used to... but keep in mind that it is work. You have to keep spammers out, decide on level of privacy, make decisions on how to set up, and the forum takes room. and if people want to share photos, and you decide to keep them on your site, they are more secure.. but photos take more room.
and there is the moderation and running the forums. although.. if the forum is quiet, it isn't like running a busy forum, which can be a full time job. But when there are problems with the forum, you or your son will be getting the messages asking for help. so.. it is a commitment.
so... think about it. The advantage is you could also create something for the HD group. But then... they might already have a good setup now (don't know).
anyway, it is work and time. but the google / yahoo groups are easy, if not the most user friendly.. but you can get email notification whenever anyone posts anything. so, this is an advantage for a group where there are posting lulls.