How long does it take before an incoming link shows up on Google's backlinks? I've had an incoming link for over 3 weeks already and its still not showing up.
Worst Case Scenario: Link comes from low-PR page, which gets crawled monthly. Day -1: Googlebot visits the linking page. Day 0: The link is added to the page. Day 29: The data dump from the Googlebot database is sent to the Google database which calculates PR and backlinks. Of course, Googlebot hasn't seen your link yet, so you miss this update. Day 30: Googlebot visits the page again and sees the link. Day 59: The data dump from the Googlebot database is sent to the Google database which calculates PR and backlinks. Day 73: The PR/Backlink update happens, but the algorithm which shows the backlinks for a site randomly decides not to display this link.