How is the value of a link calculated? Is it by the rank of the index page, the page the link is actually posted on, or an average of all the website pages?
If we're talking about pagerank, then it's the page the link is actually posted on. But the link's anchor text seems to be a more important factor than PR. Or so I hear. Hope that helps!
I also have a question related to this. Does a link on for example a PR6 page count more towards SERPS than the same link from a PR2 page if all other things are equal (link text and number of outgoing links etc)? If the answer is yes does this also apply to Yahoo and MSN?
Cheers Skeleton, I realise that PR is Googles system but i just wondered if the others had some sort of ranking system as well in order to weight the importance of pages/sites. It seems strange if they haven't.
You cannot determine the worth of a link to a search engine - because a search engine will always find different ways to measure the worth of that link, and sometimes that value with be high, and sometimes low. You have to think about the worth of a link *to you*. And if you do not know the worth of a link to you, then compare the prices of similar links in your area to give you an idea of market rates. Do be aware that market rates are not necessarily connected to actual worth to any search engine. SEO is extremely dynamic, and the apparent worth of any single link in, say, Google, could vary wildly over the years.
msn and yahoo also measure the importance of a link, something similar with PR, they just dont make it public like google does
I would say then a similar method is used for Yahoo and MSN. They rank links, and pages with more inbound links would logically more powerful than pages with less inbound links (which is the same as saying PR6 vs PR2, really).
For sure other search engines also have their own ranking algorithms and values to list their SERPs in correct order. For example there is a tool here at digitalpoint called Yahoo Web Rank. http://www.digitalpoint.com/tools/webrank/ But it is not used anymore or made invisble to public by Yahoo. It never worked for my sites.
The true value of link from any page is very difficult to determine and constantly in flux but it if you follow the simple ranking system that for each PR number there is a factor of ten increase in potency devided by the number of outbound links found on that page you will have a good sense of it's relative importance. There are numorus factors to consider if you actually want to discover a more accurate prediction of it's effect on you, including how your own site is set up, where the link points to (deep linking), Does this person have a link to someone who links with you already? (PR feedback loop). Here is a great explanation of Page rank. http://reciprocal-links-manager.com/wst_page7.html
I agree with I,Brian that you cannot assign an absolute value on any given link. That said there are several factors I consider when evaluating a link. Obviously, this is more for higher quality link trades or buying links/ads. Factors I take into account (no particular order); - Age of Site - Ranking for related/similar keywords or topics - How is the page linked to on the site - single link or sitewide? - Number of unique class C IPs - Quality of their backlinks. Are the links from link trading pages or from real pages? Nothing excites me more than to find a virgin site that has never hunted for links. - Is the link going to be on a real page or a Link Trading page? - Can it deliver traffic? ( I suspect now or in the near future links that deliver traffic will be given great weight) - Will my link be in the middle of a sentence or paragraph - Where on page will the link be located - Recent Cache - Not in supplemental results - Number of outgoing links on page - Quality of outgoing links - Title tags of page - How unique is the content of the page What other factors do you consider when putting a value on a Link?