Page is a not externally linkable
tedster - 5:34 pm on Apr 5, 2009 (gmt 0)
Matt Cutts discussed this at PubCon Austin. He said that Google doesn't treat unlinked url mentions as links, not even in a dampened fashion.
It's possible that Google picks up domain mentions from text (ie: example.com) and treats them as part of the web graph (with some dampening)