The use of this tool is to check your link popularity in the search engines.

But I , my self use Google "Who is link to your web site"

Google and Yahoo are the most important search engines owned by the same firm and a lot of other search engines like Aol, Netscape and other important search engines (not msn), get their data form Google, If your website is indexed in google, it will appear in every search engine that gets data from Google.