Anyone that is keen to follow discussions around the SilverStripe CMS should definitely join the SilverStripe LinkedIn group. On January 10th 2011 the group was made 'open' so that you do not need to be accepted into the discussion group.
At the time of this post the group has 212 active members. All of the past discussions are in an archive. Hopefully the owners of the group can allow the older content to be available.