We've started marking redirects within each one of the archive snapshots. Starting on 7/28/09 each history and article snapshot will contain a
<page> .. <redirect /> <revision> .. </page>
entry so that everyone can easily identify which articles are in fact simply redirects.
This came as a request from Erik Zachte to further improve on our stats collection and has allowed us to surface more user contributor stats that are not filled with articles lacking significant content.
--tomasz