The Logic And Use Of Sitemaps For SEO - Why A Sitemap Is A Bad Thing
(Page 3 of 4 )
For those of you unfamiliar with the pagerank algorithm, in its simplest form the relationship between 2 pages is stated by this equation: PR (A) = (1-d) + d[(PR{t1})/(C{t1})] which simply states (once you consider d=.85 (Goggles dampening factor) and PR t1= the giving pages actual weight and Ct1 = the number of links on the giving page) that when one page links to another page, it is able to pass on 85% of its weight divided by the amount of links on that page. Thus if a giving page had 100 PR weight points and 10 links on it, it would pass 8.5 weight points to each.
Now the reason for the sitemap in the first place was to get some PR to all of your important pages but what needs to be read into the algorithm is that with every link (iteration) that the spider follows, the total amount of PR available to the next recipients is diminished by 15% (remember d=.85 and an 85% pass on = a 15% loss). Consequently because a spider must first pass through the sitemap page to get to the internal pages it ends up endowing the sitemap with pagerank and causing the links off of the sitemap to receive 15% less PR weight points each vs. being linked to directly from the original linking index. This is a problem because, by their very nature, sitemaps are not the best or most logical choice for optimization as far as their on-page content goes, because - let's face it - they're sitemaps.
Now, Referring back to the original idea of linking with good architecture (extra links at the bottom of main pages), your minor pages receive the same amount of PR as they receive from the sitemap model, because they still had to be reached indirectly. The PR that would have been wasted on the sitemap has now been attributed to your main category pages, which is where you wanted it in the first place.
Next: Links Pages Attract PR, But Why Lose PR To Them' >>
More Search Optimization Articles
More By Morgan Carey
/ 12 
