I am far from certain that we (in this case meaning the Owner & Moderators of a group for which I am one of the latter) actually want to post as Owner anonymously because we always sign them anyway, often with 3 names. (Members who forget to "sign" their posts often find a "please sign your posts" added to their message before it is released. Persistent offenders have their posts rejected until they comply.)
Obviously there are no hard and fast rules about when to post as Owner but my own interpretation is to distinguish the message as relating to the operation or management of the group as distinct from normal traffic.
I would prefer my name to be replaced by Owner / Moderator or something like that so that the members can see the distinction more easily. I would still sign the message either with my own name or all 3 as mentioned above, but of course my view is only one amongst many on this forum.
Any further suggestions? The ability to Reply as an Owner seems to be agreed amongst those who have commented, but if this discussion is to be converted into a #Suggestion on betagroups then there is going to have to be something that looks like a consensus first.