See the mailing list thread [[http://www.ntg.nl/pipermail/ntg-context/2003/002053.html]] for more on this.
===Headings numbered independent of chapters or other headings===
If you want a heading that gets numbered without resetting at new sections or chapters (for example, for problems whose numbers increment throughout a book), here is a solution due to Hans [http://archive.contextgarden.net/message/20030415.153451.374310d8.en.html on the mailing list]:
<texcode>
% use a lower level head
\definehead
[Problem]
[subsubsubsection]
% cleaned up
\setuphead
[Problem]
[style=\ss\bf,
color=red,
before=\blank]
% use a label text
\setuplabeltext
[Problem=Problem ]
% use your own numbers
\setuphead
[Problem]
[ownnumber=yes]
% increment and feed
\newcounter\ProblemNumber
\def\problem#1%
{\doglobal\increment\ProblemNumber
\Problem{\ProblemNumber}{#1}}
% nicer here
\setuplist
[Problem]
[alternative=c,
criterium=all,
width=2em,
interaction=all]
% the test
\starttext
List of Problems
\blank[big] \placelist[Problem] \blank[big]
\section{Tufte}
\input tufte
\problem{First problem}
The first problem description.
\section{Another Tufte}
\input tufte
\problem{Second problem}
Second problem description.
\stoptext
</texcode>