Q:

How should the tag [graph-algorithms] be used?

How should the tag graph-algorithms be used?  In particular, should it be used together with graph-theory, should it be used exclusively of graph-theory, or does it depend on questions?
Currently, I fail to see any difference between the questions tagged as graph-algorithms and the questions tagged both as ds.algorithms and graph-theory.  Many questions are actually given all of these three tags.
If there is a guideline how to apply these tags to questions about graph algorithms, it is probably better to explain it in tag wiki.

A:

In general, we need the most specific tag relating to the question. So I can easily imagine graph-algorithms being more specific than graph-theory. Also, ds.algorithms is special in that it's an arxiv tag, and we have desired as far as possible to keep at least one arxiv tag for each question. So I'd say the main distinction is between graph-theory and graph.algorithms, and the wiki for graph-theory could say something like

If your question pertains specifically
  to algorithms on graphs, you should
  use the more specific
  graph-algorithms

and the wiki for graph-algorithms could say something like

This tag is specifically for
  algorithms on graphs. For more general
  graph theory questions, please use
  graph-theory

ds.algorithms itself should emphasize that it's an arxiv tag, with something like

ds.algorithms is a component of the
  arxiv cs.ds categorization, and should
  be used on all questions that relate
  to the design and analysis of
  algorithms. While the design and
  analysis of data-structures also
  includes algorithms, the more specific
  ds.data-structures should be
  used for those questions. For
  algorithms in computational geometry
  for example (which has its own
  top-level tag cg.comp-geom,
  algorithmic questions should use both
  ds.algorithms and cg.comp-geom.

