Future - 2:13 pm on Nov 9, 2010 (gmt 0)
Thank You for clarifying.
I assume you are referring to registering expired domain names (niche-specific which were found via old directories and has backlinks).
I do beleive, this should have some potential (but not really great as the domains went offline with no content)
Register this domains, build some content and leave it.. we can use them to link to our active sites.
Though I am still confused here:
3) I check backlinks for oldsite1 and oldsite2 and find they still has 20 backlinks each. I check each of those 40 sites and fire off an email where I point out the page that has the broken link and ask for a link to my site while they're fixing it.