Sergio Carracedo 
With the proliferation of ‘social’ plugins, which are present on more pages every day, private browsing was starting to become a utopia. For example, simply by having an open session (or not) on Facebook, every time we enter a website that has an innocent “Like” button, we can be identified.
This doesn’t mean it’s being done, but the possibility is there. The website we visit doesn’t know (or doesn’t need to know who we are), but the social plugin does know who we are and which website we are visiting, since it has our social network session and the page requesting to display the plugin.
If we use Chrome, Firefox, or Safari to browse and would like to prevent this from happening, we’re in luck:
Created by former Google employees, https://disconnect.me/ is an extension for Chrome, Firefox, and Safari that, according to its own creators, blocks requests to Google, Facebook, Twitter, Yahoo, etc. servers, preventing them from ‘tracking’ us in our browsing outside of these sites. We have the option to disable the block for the page we are currently visiting, in case we want to “Like” something, which it will remember for future visits.