Hyper-Links

Links 

Links (or hyper-links) are really the heart of HTML page building. The biggest strength of HTML is
the ability to link to other documents. A link, in the context of HTML is denoted as <a
href=”www.yahoo.com”>www.yahoo.com</a> The link will appear as www.yahoo.com on
your website. This will take visitors of your site to Yahoo.

Links can be checked and followed followed by so-called link checker programs. These
programs search HTML source code for the <a href=></a> tags and then create a file or index
of the found links. Spammers will often use this technique to find email addresses or contact
forms they can use to spread their mass emails.

Link checkers can also be used to check your website for “broken” links or links that don't go anywhere. This can happen a lot even in
relatively small sites.