11. PR0 - Google's PageRank 0 Penalty (continued)

The Combination of PageRank and BadRank to PR0

If we assume that BadRank exists in the form presented here, there is now the question in which way BadRank and PageRank can be combined, in order to penalize as much spammers as possible while at the same time penalizing as few innocent webmasters as possible.

Intuitively, implementing BadRank directly in the actual PageRank computations seems to make sense. For instance, it is possible to calculate BadRank first and, then, divide a page's PageRank through its BadRank each time in the course of the iterative calculation of PageRank. This would have the advantage, that a page with a high BadRank could pass on just a little PageRank or none at all to the pages it links to. After all, one can argue that if one page links to a suspect page, all the other links on that page may also be suspect.

Indeed, such a direct connection between PageRank and BadRank is very risky. Most of all, the actual influence of BadRank on PageRank cannot be estimated in advance. It is to be considered that we would create a lot of pages which cannot pass on PageRank to the pages they link to. In fact, these pages are dangling links, and as it has been discussed in the section on outbound links, it is absolutely necessary to avoid dangling links while computing PageRank.

So, it would be advisable to have separate iterative calculations for PageRank and BadRank. Combining them afterwards can, for instance, be based on simple arithmetical operations. In principle, a subtraction would have the desirable consequence that relatively small BadRank values can hardly have a large influence on relatively high PageRank values. But, there would certainly be a problem to achieve PR0 for a large number of pages by using the subtraction. We would rather see a PageRank devaluation for many pages.

Achieving the effects that we know as PR0 seems easier to be realized by dividing PageRank through BadRank. But this would imply that BadRank receives an extremely high importance. However, since the average BadRank equals 1, a big part of BadRank values is smaller than 1 and, so, a normalization is necessary. Probably, normalizing and scaling BadRank to values between 0 and 1 so that "good" pages have values close to 1, and "bad" pages have values close to 0 and, subsequently, multiplying these values with PageRank would supply the best results.

A very effective and easy to realize alternative would probably be a simple stepped evaluation of PageRank and BadRank. It would be reasonable that if BadRank exceeds a certain value it will always lead to a PR0. The same could happen when the relation of PageRank to BadRank is below a certain value. Additionally, it would make sense that if BadRank and/or the relation of BadRank to PageRank is below a certain value, BadRank takes no influence at all.

Only if none of these cases occurs, an actual combination of PageRank and BadRank - for instance by dividing PageRank through BadRank - would be necessary. In this way, all unwanted effects could be avoided.

11. PR0 - Google's PageRank 0 Penalty (continued)

This article reproduced with permission of eFactory.
© 2002 eFactory Internet-Agentur KG Online-Marketing - written by Markus Sobek
PageRank and Google are trademarks of Google Inc., Mountain ViewCA, USA.
PageRank is protected by US Patent 6,285,999.