I am Glenn Tuley, a descendant of the Tuley's who migrated to southern Indiana in the 1820s.
What is the "Mirror Site".
The Mirror SIte is another web server (differernt than my www.tuley.us site) with an exact duplicate copy of the genealogy data. So, if my web site goes down (or I am upating my web site and the normal links stop working), you can access the data at the mirror site.
Why we do it.
I have a B.A. in History and a M.S. in Computer Science, so doesn't it make sense that I would have a genealogy web site to combine both fields?