According to BruceClay.com (a reliable source), 499 out of every 500 webpages are not indexed by search engines. If any of those "invisible" webpages include a link to your website, that's a lost opportunity to improve your search engine rankings, because you don't get credit for links that search engines can't see.
Search engines have limited capacity to do their indexing, so they must be highly selective about which pages to index. Since the index selection process differs at Google, Yahoo, and MSN, it's quite common for a page to be indexed by one of those search engines but not at the others. In fact, Bruce Clay estimates that there is as little as 11.1% duplication in indexing.
So, if a given webpage links to you, it's quite possible for Yahoo to know about it, but not Google or MSN. Similarly, it's quite possible for MSN to have indexed a page that links to you, but not Google or Yahoo. And so on.
When your website's link popularity is undervalued, your rankings in search engine results are not as high as they could be.
Therefore, conduct queries at each major search engine to create a master URL list of webpages that link to you. Use this search query format:
link:redcross.org (change "redcross.org" to your website address)
Once you create your master list of URLs that link to you, submit them for full indexing at Google, Yahoo, and MSN by using these forms:
If you don't have the time to do this manually, Bruce Clay offers a LinkMaps subscription service that automates the process: http://bruceclay.com/web_linkmaps.htm
LinkMaps will:
- query major search engines to create a list of external webpages that link to your website
- de-dupe the list of referrer
- spider all of the URLs in the list of referrers to verify that the links to your website still exist and are "crawlable" by search engines
- submit the list in a file that will cause search engines to more fully index the webpages that link to you, thus increasing your visible link popularity, which should also lead to increases in your search engine rankings
