On the weekly Distrowatch News, they comment on the decision to drop certain less popular architectures from Etch.
The Distrowatch comment is found here and the original announcement about the qualification results is here.
That does leave four ports released with sarge which are not consideredrelease candidates for etch at this time. Those ports are arm, m68k, s390, and sparc. We'll go into the details of which criteria are not currently met by each architecture further on, but first, to the porters of these architectures, let me assure you that this is not the final word on the subject.