Do you know that when your browser connects to a particular site, it can also connect to other invisible sites which users have no idea about. For example, Facebook runs its Javascripts of another domain which is fbcdn.net.

Sometimes these invisible sites also track your usage and store information about your browsing activity. Collusion is a handy Chrome and Firefox extension which helps users check if the sites they are visiting are also connecting to other invisible sites.

Just install the Collusion extension for Chrome(https://chrome.google.com/webstore/detail/collusion-for-chrome/ganlifbpkcplnldliibcbegplfmcfigp) and start surfing. The collusion icon shows the number of sites that are informed from the page you are viewing.


The sites with a red circle are the advertisers while the grey circles connecting are usually social media sites.

Not all invisible sites which are informed about a visitor are dangerous. Most of them are not. For example most blogs will inform Google Analytics about a visitor.

If user clicks on “Block known tracking sites” the extension then shows which advertisers are known trackers and are blocked. They are displayed in the visualization with a blocked symbol.