How malicious parties can spam your site
Malicious visitors to your site can create spam through mechanisms such as comment spam, forum spam, and freehost accounts. Learn about these tactics and how to prevent them early on.
Check out our Webmaster Guidelines here: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=35769.
Read more about rel="nofollow": http://support.google.com/webmasters/bin/answer.py?hl=en&answer=96569.
Learn more about creating great sites that perform well in Google search results at Webmaster Academy: http://support.google.com/webmasters/bin/static.py?hl=en&page=checklist.cs&tab=1095542
More videos: http://www.youtube.com/GoogleWebmasterHelp
Webmaster Central Blog: http://googlewebmastercentral.blogspot.com/
Google Webmasters: http://www.google.com/webmasters