I have a site ranking on the second page for a keyword whose first page is dominated by PR7 sites. So I was shocked to see today that a site that was just registered 3 days is ranking #1 for this keyword. It has 0 backlinks (obviously) so the only way it could be receiving any link juice is through 301 redirects. Is it possible to check a site for any 301 redirects that are pointing to it? Also, would be a good idea to buy expired domains and redirect them to your existing sites for the purpose of passing pagerank? (it's obviously working for the site ranking #1)...