putting together a doc for someone - I know part of the current strategy is to 301 throwaway domains - last time I had a rummage I couldn't find a tool which would trace inbound 301's from a url, is this something majestic or moz or someone now provide?
Not worth my spending any real cash on this as I can ask for an official list before I get too deep into things, but it would be interesting to see what they are, and seems strange no one with a big crawl has released this as a service yet.....
pretty sure opensitexplorer/seomoz has a filter for links via 301s
ahrefs has an option called redirects that should show you which domains are being 301'd to the site