XTM export has been available on Subject-centric blog from the first day. But, I think, it was not obvious what readers can do with it. I added a link to Subject-centric topic map in Omnigator (Topic Maps browser).
I also recently made XTM export compatible with Expressing Dublin Core Metadata Using Topic Maps recommendations.
My plan is to connect (aggregate) Subject-centric with other Topic Maps related blogs based on core “Subject-Resource” and simple “Blogging” ontologies.