1script - 4:51 pm on Apr 30, 2010 (gmt 0)
I would not worry too much about the example you've given: on any large and old site (as yours appear to be) you really need to sift through hundreds if not thousands of examples for the result to be of any statistically significant value. It may simply be a fluke. Else it could just be that neither G* nor Y! list a very good external page that sits somewhere in the depths of the old Internet and provides that seemingly abandoned page of yours with a link juice you don't know about. I have a few of such "accidentally discovered" links myself. This theory actually goes very well with the recent idea that G* is giving much more value to external links and discounts internal.
Also, I've been following your posts because I have sites in an apparently similar situation - long tail SERPs are deeply depressed for the last 6 weeks. On multiple occasions you talk about your competitors' traffic situation with such certainty as if you have a man on the inside. Unless this indeed is an insider info, you are probably going by third party data - Alexa, Compete etc. However, I'm looking at my own data from both of those sources - and they are approx. 50-60% off. Besides, they only catch up with traffic trends in approx. 2 weeks (Alexa) or 1 month (Compete). So, is there a better source of relevant traffic info about other sites in the SERPs one's interested in? Would be very nice if you can share.