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Probably a lot of issues here.
Thanks,
SkinnyJoe
1. Google Directory (directory.google.com) starts with PR10 and DMOZ (www.dmoz.org) starts with PR9.
2. The internal linking is different.
Just as an example; if you go in ODP to top/world/<language1>/<cat_a>/<subcat_b> you can see a link to top/world/<language2>/<cat_a>/<subcat_b>. In Google Directory you don't see these links.
3. Different incoming links on the categories.
Both directories have links directly to sub categories. A link doesn't always go to the homepage of a site. But pages link to a category in ODP and not to the same category in the Google Directory (or to ODP but not to Google Directory).
4. Google Directory links to ODP profiles
On a lot of pages, there is a link to the profile of the editor. The editor's profiles exist only on ODP. From these profiles, there are links into ODP. There are no links from ODP to Google Directory (okay, there is 1 in 'Sites Using ODP Data').
5. Through the profiles some categories get a boost
Some editors, who are allowed to edit high categories, also have a link to a very low category for some personal reason.
Maybe I miss some other reasons, but I think these 5 already explains why the PR isn't always the same.
[edited by: takagi at 12:33 pm (utc) on April 8, 2003]
The internal linking structure between the Google Directory and DMOZ are different, so PageRank can vary between the two.
Here's a couple of examples.. in dmoz.org, the existence of the editor profile pages changes the structure, the front page is different, the pages could have backlinks from outside the directory itself.
So, to give an example, look at a page with a link from the front page of dmoz.org (PR9/10ish), but not directory.google.com (PR10+), in this case the UK directory, Regional/Europe/United_Kingdom/ - in dmoz.org, the front page PR9 gets passed straight down to that category as a PR8, in Google only a PR7...
..now click on the last editor name in that category (note, this is a random choice). You'll notice that particular page has a PR7. Click on the SECOND link in the category list and you'll see that the resulting page has a PR6, which is actually one higher that the parent category.
dmoz.org has been around for nearly five years, so it will also have more backlinks to it than directory.google.com. According to Alltheweb, dmoz.org has 716,519 backlinks, and directory.google.com 283,824. Where those are deeplinks, this will add PR to the lower levels of the dmoz.org directory.
I guess I have been spending waaaaay too much time looking at PR in dmoz.org :)
So my question is, does Google actually spider the Google directory AND the ODP, or just one? If just one, which one? If it's only spidering the ODP, then this thread is largely irrelevant, because the PR in the Google directory won't affect anything.
Since both sets of pages have PR I assume that both are spidered.
I am pretty sure that the Google directory is spidered, as it is not excluded in Google's rather long robots.txt.
The ODP must be spidered, since new sites added to it while the RDF dump was not working were found by Google.
If PR measures importance, it seems problematic that pages with such obvious similarity would have greatly different importance.
The PR discrepency could be an Undervalued/Overvalued indicator, where searchers are oversupplied or undersupplied with content.
<added>Content is read by humans, who choose to link, or not link, to the page. People decide how "important" or otherwise a page is, Google just observes their linking behavior. Of course, reciprocal linking plays havoc with the fundamental assumption :). </added>
Dmoz will give higher pagerank to baseball sites, while Google will diminish baseball but value football sites.
dmoz.org and directory.google.com are ideal because of their high PageRank.
