How to index links
The links in a document can be included in the search index.
For example, a web page with a link to "www.xav.com" can have that address stored in the index file, even though the string "www.xav.com" doesn't appear anywhere in the text of the page. Users will then be able to find this document by doing a search for "www.xav.com", or by doing a search for "link:www.xav.com". The word "link" is a special attribute search type for documents which link to a specific website.
This feature takes up extra space in the index file, and so it is off by default. To turn it on, go to the Admin Page, choose General Settings, and edit setting "Index Links".
"How to index links" https://www.xav.com/scripts/search/help/1052.html