LaTeX: Label naming conventions

The common convention seems to be to use : as a separator between words in the label.

\label{foobar}
\label{sec:programming}        % Section on Programming.
\label{sec:programming:python} % A subsection on Python within the Programming section.
\label{fig:swineflu}           % A figure on swine flu statistics.
\label{tab:population}         % A table on population numbers.