DSSSL is a parsing language for SGML, sort of a predecessor to XSLT for XML. In fact, XSLT borrows a great deal of its logical theory from DSSSL. However, DSSSL is also something of a behemoth in comparison, and is not syntactically similar to XML or XSL. In fact, it's syntax is based off of LISP. I don't know of any sites that use it for page generation off hand, although it seems like that would be like using Java 2 Enterprise Edition to create a script to organize your mp3 playlist. :-)
This information courtesy of "Teach Yourself XML in 21 Days," which I am almost through reading.
--Larry
