What Google Sees
It's important to know how Google perceives your website, and as a result webmaster need to ask themselves 'What do Google see?'. If you hide content from your users for example, but show it to Google, this is bad and it called Cloaked Content. This is a black hat SEO tactic that rarely works for long term SEO campaign. This tool can aid you in finding out if your website does this for any of your content by showing you something similar to what Google sees.
Simply enter your URL and you will be shown the HTTP headers and the full HTML code seen by Google.