Also note the placement of this redirect tag. Do not place as the first tag in the Head. Search Engines are spam conscious. I suggest installing the Robots tag before this one, and both at the end of the important META tags. Also, when redirecting to a mirrored site , please redirect to the same page on the mirror .
Viewers are finicky.
You do not want to loose your viewer. This would allow all of the files and links to be indexed. There are some that do not want their pages to be indexed by the spiders. This tag was designed for this problem. This will tell the spider not to index this page, but would allow it to follow links and index the linked pages.