I can't be absolutely sure about this but this is what seems to be happening and is in my opinion a major deficiency in the algos.

We all know that both onpage factors and inbound links contribute to ranking. If would seem reasonable that these two factors are combined in some ratio. But what if a site has minimal onpage content value but, to exagerate, say a billion in-bound links. If the 'scores' are simply added, pages with little real value can get a high ranking simply based on IBLs to the site as a whole. It would e better if there was a cap to the influence of IBLs but that doesn't seem to be the case. Implementing that would produce better results.

Steve

An alternative or addition to a cap on IBLs would be to consider the square root of the IBLs quantity, or even cubed root. A single link would gain a weighting of 1. A 100 links would gain a weighting of about 3 and 1000 a weighting of 10. Given that huge numbers of IBLs are suspect this still gives considerable weighting to IBLs without gross distortion.