It may be because of the way Google and Yahoo calculate the inbound links. For example if you post a article in an article directory with PR Zero – Yahoo may consider the link an inbound link whereas Google may not consider it as an inbound link. Remember this – Google is more *strict* in considering and accepting an inbound link.

Yes its true that Google excludes links generated from within the site itself – else webmasters would have linked their sites too many times within the site to “inflate” PR (page rank). This I think would have definitely irritated the search engines.

There is more to it. Google infact does not even count some incoming links from irrelevant pages, not very important sites / pages, and incoming links from the same IP. Google stopped counting incoming links from the same IP when webmasters bought many domains on a shared host and linked them internally to increase the PR.

I hope you understand that its not that easy to buy many domains and host websites in different IPs (or different webhosts). Though its not impossible.

Let me also tell that for some strange reason Yahoo Site Explorer is a very popular tool among webmasters. Though personally I feel Google gives an accurate estimate of inbound links.

So to answer your question, it’s a good idea to use Google to know the real inbound links to your site, nonetheless does it harm to check what Yahoo Site Explorer says about your site? After all many webmasters will check Yahoo before giving your site a link.

Hope that helps.

Jack http://seoapplied.blogspot.com/