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Q: How does Google PageRank work ( Answered 5 out of 5 stars,   1 Comment )
Question  
Subject: How does Google PageRank work
Category: Computers > Algorithms
Asked by: respree-ga
List Price: $5.00
Posted: 10 Jan 2003 09:41 PST
Expires: 09 Feb 2003 09:41 PST
Question ID: 141243
I am completely confused about how Google's PageRank works.  I thought
I understood the basics, but evidence leads me to believe I don't.

Assumptions:
1. PageRank is created by one site linking (voting) to another.
2. More votes means better ranking.
3. Links from sites with high rankings (quality sites) means better
ranking.
4. It takes 4-6 weeks for the googlebot to index a page and calculate
PageRank.
5. Pagerank is 'page-specific', not domain-name specific (i.e. a
site's home page could have a very high ranking, but if its inner
pages remain either unindexed or nobody linked to its inner pages, the
PageRank for these inner pages would be low or zero)
6. Googlebot (in creating its PageRank) treats every site the same
with respect to PageRank including google.com.

Here is what leads me to believe the one or more of the above
assumptions is not true.  I posted a question yesterday, and already,
it has a PageRank of 8.  It doesn't seem plausible that:

1. Anybody in their right mind would link to this page
2. That the page could get indexed that quickly
3. Even if #2 were true, it seems like it would take weeks to
calculate the PageRank.

Here is the page I'm referring to:
http://answers.google.com/answers/main?cmd=threadview&id=139926&m=r

My question:  How is this possible? Any ideas/opinions?
Answer  
Subject: Re: How does Google PageRank work
Answered By: webadept-ga on 10 Jan 2003 10:05 PST
Rated:5 out of 5 stars
 
Hi, 

Only part of your assumptions are correct, as you have already
perceived. PageRank does rely heavily on outside links, but also,
internal links and the content of the page. Each page does have it's
own PageRank, but if PageRank is not yet calculated for a specific
page the default PageRank relies on the placement of that page in the
directory scheme. For instance, if your main page is a PR-5 and you
add a page to it today under a level two directory say some thing like
/mydocs/newpage.html, then newpage.html will probably show a PR of 4
or 3 depending on the rest of your site and its various variables. It
won't have a PR of 0.

Calculations of PR happen about once a month, you are right about
that, but it doesn't take several weeks to do the calculating. If that
were true, nothing would get done.

Here's part of an article I wrote which will go through the internal
linking needs for a site, and below are several links to help you get
a better understanding of how PageRank works:

To get your Page Rank up you need to pay attention to the foundation
design of your website. The menu systems, links to internal pages from
front pages, from bottom tier pages back to higher levels, and several
other factors. We're going to go through some of that here.

On most sites, the first page, or the index.html page is going to have
the highest PR rating. This makes sense, it being out there getting
hit all the time, and if someone else is linking to you, its probably
that page, but you still need to watch how this happens to get the
best effect for your total site.

Lets say your site has three levels of pages. The first is the
Index.html, at the top of the pyramid. The next level is your About
Us, Contact, News, and Items for Sale, cover pages. The third level is
full story pages, product pages, and the more detailed info pages that
your site is offering. In standard design, the top index page is going
to link to the menu pages, and then those main menu pages are going to
link down to the more detailed pages on the third level.

Let's give your site a Page Rank of 6 on the top level, the
index.html. This is a really good ranking by the way, this means lots
of websites like you and you are doing something right. As the links
happen, and we go down into your site, we'll see that the second level
pages have a rating of 5 on the PR bar. Going further down to our
product pages we see that these detail pages have a level of 3, or
even 2 on some of them.

This type of PR dilution makes sense to the robots, but our bottom
layer pages is often where most of the details of our websites lie,
and the content that will bring into our site the web searcher looking
for information on the web. We want these pages to show up better on
the search engines and have higher page rankings themselves.

That these pages have poor PR doesn't necessarily mean that they will
not place well on the search listings, some place very well, but the
better rank they have, the better our whole site will place.

The guys over at Top Site Listings came up with a good checklist. I
don't know much about their company, but many of their articles are
sound in reason and accuracy. You might want to check them out.

* Make sure that your primary page(s), the index.htm page, links to
your secondary pages or secondary levels.
* Make sure that your secondary pages link to each other 
* Link your secondary pages to the third level pages within their
sub-directory, sub-domain, or level
* Link the third level pages within each specific sub-directory or
sub-domain to each other.
* Link the third level pages back to the secondary page that it was
linked from
* Make sure that the there is not heavy linking between third level
pages
* Link to pages, regardless of level, that are relevant 
* Link to pages, regardless of level, where the text on the page being
linked from is keyword specific to the page that you are linking to
* If there are fourth level pages, follow the same linking structure
that has been laid out in this checklist

Other reminders:

* Only link pages within your site that are relevant to each other 
* Use keyword specific link text when linking between pages 
* Use standard HREFs in links that are easy for the search engine
robots.
-----

After you take care of this, you are going to want to add to your site
a "Site Map" and a robots.txt. These are going to help all the pages
on your site to get indexed, once you work out that directory problem
you have there.


Read these pages for more information. 

Search Engine Optimization 
http://hotwired.lycos.com/webmonkey/01/23/index1a.html
 
Top Site Listings 
http://www.topsitelistings.com/ 
 
Reasons your site may not be included  
://www.google.com/webmasters/2.html#A1  
  
Google Technology      
://www.google.com/technology/      
      
Google's PageRank and how to make the most of it      
http://webworkshop.net/pagerank.html      
     
Google Under the Scope    
http://www.searchengineworld.com/spiders/google_faq.htm    
     
PageRank: Bringing Order to the Web    
http://hci.stanford.edu/~page/papers/pagerank/    
     
The Anatomy of a Large-Scale Hyper-textual Web Search Engine     
http://www-db.stanford.edu/%7Ebackrub/google.html     
    
 
    
Thanks,  
 
webadept-ga
respree-ga rated this answer:5 out of 5 stars
Thank you for your response.

Comments  
Subject: Re: How does Google PageRank work
From: robertskelton-ga on 10 Jan 2003 22:16 PST
 
I agree with webadept. If the site has some pages indexed, an
un-indexed page will be given a guess PR in the GoogleBar. This
question has not been indexed, in fact Google have a robots.txt file
which instructs GoogleBot not to:

User-Agent: *
Disallow: /

User-Agent: googlebot
Disallow: /answers/main?cmd=currentquestions
Disallow: /answers/main?cmd=threadview
Disallow: /answers/main?cmd=search
http://answers.google.com/robots.txt

Not indexed, because a search for this quote does not find it:
"but evidence leads me to believe"
://www.google.com/search?q=%22but+evidence+leads+me+to+believe%22

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