Hi Brendan,
Alerts can't be generated by new posts I'm afraid, they can only be generated when you select to follow a discussion that has been started.
On a related note however, we are looking into the possibility of gettings alerts automated for group discussion updates, as some people have commented that the groups are not getting as much activity as they should as group members are not made aware of what is going on in them. However, some people could potentially find this annoying. We are going to canvas the group managers to see what they think first, and will let everyone know what the breakdown of support is for it.
Regards,
Deirdre
