I'm working on a document with both chapter/section numbering, and a 'topic' whose numbers are sequential across the entire document. I found a solution to enable this from a 2003 thread in the archives ("Creating list with separate numbering", 15 April 2003), but I can't seem to get references to work. I've looked through the archives, read The TeXbook, and browsed the ConTeXt source but can't quite figure out how to make this work.
% "topic" numbering
\definehead
[Topic]
[subsection]
\setuphead
[Topic]
[ownnumber=yes,number=yes,numberstyle=normal,numbercolor=darkgray,textstyle=\it,alternative=inmargin,header=empty,inbetween=,after=]
% use a label text
\setuplabeltext[Topic=\S]
% increment and feed
\newcounter\TopicNumber
\def\topic[#1]#2
{\doglobal\increment\TopicNumber
\Topic{\TopicNumber}{#2}}
\starttext
\section{Tufte}
\input tufte
\topic[topic:SomeTopic]{Some topic.} Here we will discuss a particular topic.
\topic[topic:AnotherTopic]{Another topic.} Let's expand on the previous topic.
\topic[topic:AGreatTopic]{A great topic.} I can go on like this all day.
\section{Another Tufte}
\input tufte
\topic[topic:SomeOtherTopic]{Some other topic.} Recall in \in{\S}[topic:AnotherTopic] that we extended blah blah from \in{\S}[topic:SomeTopic] and noted that...
\stoptext