There may be some scenarios where you don't want Google following a specific link on one of your web pages. This is easily achieved by using this 'nofollow' code snippet.
You're probably familiar with 'nofollow' being used in a meta tag to stop a page being indexed like so:
This can also be used in individual anchor tags, so stopping Google or other search engines following a link is as easy as this:
<a href='/my/url' rel="nofollow">Google Won't follow me!</a>