Google Bowling typically happens when you link bomb your site with too many similar links. For example, if you have a site about “purple widgets” you don’t want to have thousands of inbound links with the anchor text “purple widgets” - you should have some links that say “widgets,” “purple,” “nice widgets,” “new widgets,” “buy widgets,” etc.

By varying your anchor text you can build thousands of inbound links (over a period of time to avoid the over optimization penalty) without being heavily penalized by Google and any other engines that actually have relevancy filters.