Backlinks

Backlinks, or incoming links or "links to" are links to a URL found on other URLs.  They may be internal links, such as 21cif.com/ found on 21cif.com/tutorials/ or external, as in the case of 21cif.com found on coolhub.imsa.edu.


External backlinks may be valuable in researching the credibility of a site.  Backlinks help to answer questions like, Who links to 21cif.com? Why? Do they have any authority?


For years, a good way to find backlinks to a page was to use the link: operator  (e.g., the query:  lilnk:21cif.com). Search engines have made changes to link: so that fewer results are obtained. 
Yahoo.com did away with link: altogether.  Google is probably still the best choice, but they return only a fraction of what they once did.


This is where specialized search engines and databases comes in handy. 


Open Site Explorer (http://www.opensiteexplorer.org/) provides more complete backlink results than Google. It's a free service and easy to use. Results can be filtered to eliminate all the internal links.


Using a backlink checker is a step in the investigative search process. But just knowing how many backlinks there are isn't enough. Evaluating the referential credibility of a link target requires looking at the (representative) sites to see if they have authority and why they are a backlink.  Who would you expect to backlink to 21cif.com if it is a reputable site?


Who do you find?