You may have seen on eBay and other auctions high pagerank (PR) domains for sale. You may have even considered purchasing one of these domains. How do you ascertain the value of such a domain?

First of all, you must verify the PR by using a free tool such as http://www.seologs.com/pr-check/pagerank.html. You just enter the domain name that you are thinking of purchasing. This site will tell you whether or not the domain actually has the PR that the seller claims.

Then, even if the site has a high PR, it still may NOT be indexed by Google, and if a site is not indexed, that's sort of like a word not being in the dictionary. Google may think it's a great word based on the PR, but if they don't index it, it won't be found in Google's "dictionary."

It may seem inconceivable that Google will give PR to a site they don't index, but I've seen it happen many times. Google explains it's because the algorithms that index sites are constantly updating, but the algorithms that calculate PR update less frequently, and sometimes the two processes are not in synch.

Be that as it may, I've seen high PR domains for sale that are NOT indexed in Google. What you can do to find out whether the domain is indexed in Google is to type site:www.nameofthedomain.com into the search bar. If Google comes back with a page that says, "Your search - site:www.nameofthedomain.com - did not match any documents" -- well, the site is not indexed in Google.

You can try the same thing in Yahoo and MSN and see if any pages are indexed in those search engines. If the domain is well-indexed in Yahoo and MSN, and getting a lot of traffic, it may not matter if the domain is not indexed by Google.

However, another important factor in purchasing a domain is how many backlinks, or links from other sites, the domain has. You can type link:www.nameofthedomain.com into Google, and it will tell you which sites are linking to the domain. Once again, I've seen sites with high PR that only had one or even no backlinks!

If you are considering purchasing a domain with a high PR that is not well indexed or doesn't have many backlinks, you've got to stop and think for a minute. Google has made it well known that it considers relevant backlinks, among many other criteria, in assessing PR. Now if the domain has no or few backlinks, how long do you think it will keep its PR?

So when considering the purchase of a high PR domain, be sure to perform your due diligence. Two other free tools that will help you are http://reladvance.com/metrix/find_metrics_results.php and http://www.linkpopularity.com. Always check out every aspect of the domain -- PR, indexing, and backlinks -- using several independent tools. None of the tools are 100% accurate at any given moment, and so it's to your advantage to use them all and compare results.