Case: we have a page with a link to another page and that page redirects to a movie. (this is only to showcase the problem)
snippet:
<a href="redirect.aspx" target="_blank">movie</a>
in redirect.aspx we redirect to the movie.
snippet (from redirect.aspx):
Response.Redirect ("movie.avi", true);
When we click on the link a new window opens up, with the movie contents as text (???) instead of opening the default application for mime type video/avi. If wedon't do a redirect then the default application just starts up.