Users are allowed to choose uri in part. I.e. http://domain.com/chosen_by_user/
They can also change this later, in which case we keep the old uri for a month, so that people who have bookmarked the page will get a 301 and be redirected.
We also want to clearly show a visitor that they were redirected by displaying something like "This page has been permanentely moved to: newuri"
One simple solution would be to set Location: newuri?redirected, but it does not look as nice. However, I'm mianly curious about what this does to SEO. Will the page get a penalty for existing with (pretty much) identical content with and without the query string?
I'm thinking about setting a cookie instead, but not all users have them enabled. What to do?
