So I've been moving a 10 year old, well-ranked site to a domain I bought for it about 2 years ago. This site started off as a sub-directory in one of my old content sites. Because of the ranking, over the past 2 years I co-joined the domains by sharing the same navigation but each had its own uniques content. New content and features have been added sloooowly to the new domain while the old was maintained and updated, the theory being to introduce the spiders to both gradually (but concurrently) so there'd be no shock from any transition. Now I've made the move, starting at the bottom of the pyramid and worked up. I've done all the nitpicky crap we seos hate to do --proper, deep-linking redirects, orphan frame reassemblers, everything ...nothing left but the old index page.
Then I start deep-searching the backlinks, just double-checking. I know I'm never going to get all the third-party legacy backlinks straighten out (that's why I was so meticulous with the redirects). And then I find it ...I have a 10 year old backlink from NCSA Mosaic --the first browser.
Two immediate thoughts:  Wow! I'm old.  Whoa! Even though this move has been at a glacial pace, go even slower here.