Maybe they mean this one?
Perhaps we could jump in and make that one happen?
Interestingly enough there was a discussion about it:
I have added my reply ;)
"I'm just coming from the now merged and deleted SilverStripe CMS stack exchange site proposal... we started this last week after a really great wider community discussion and looks like we are not even going to get the change to prove that we can get a critical mass... which is a shame really.
I can understand the reasons for wanting to lump all CMS's together... however our SilverStripe Community of Practice is mostly concerned with how to write specific SilverStripe Framework code and how we together share our specific code related problems and improve as SilverStripe Practitioners.
We currently do this on forums, but the functionality we can get via a stack exchange site helps to reinforce best practices and quality shared experiences and learning in working with SilverStripe (we could try to duplicate this functionality over on the forums but that is really double handling isn't it?).
SilverStripe is an interesting beast... it is both an MVC Framework AND a CMS in one... I would say from having worked in many CMS's over the last 10+ years I have not really come across anything similar at an open-source level and would say the types of discussions forming around it in the community would be largely different to those in other CMS's, hence the proposal.
Either way... if you really want to merge everything... I'm sure the SilverStripe Community will adjust and still participate, who knows perhaps it will be a platform to convert users of other CMS's over to the Framework and CMS we love to work in ;)"