Google is a search engine which contains most of Internet’s available data. It crawls every site worth crawling. Google’s another resources are Google News, Google Blog, Google Base, Google Video, Google Images and other Google search engines.
Google also contains various tools such as operators which can be used to query Google for extracting specific data request about your website.
There are commands like site:, link:, inurl:, inanchor:, allinanchor: etc. Find links on websites which link to your blog. Subscribe alerts on who is linking and talking about you.
Run Link, intext commands on Google Views, Google Video, Google Blogs etc to find out on how much of presence you have on various websites. Find links and content through Google Webmaster central. Google Trends for websites and terms.
Finally you can say that it is easy to track and monitor the presence of your website and links across internet and find who is talking about your site and any other site for that matter.
In social media it is even easier as you can always track to user profiles who have posted, dugg or commented on your post, article etc.
Getting more visibility on Google is the main idea of any SEO and webmasters
