A system and method for securing access to sensitive content on the web is disclosed. The approach automates compartmentalization practices for accessing different kinds of content with different browser instances. The automation is transparent to the user and does not require any modification of how non-sensitive content is accessed. For sensitive content, a Fresh Browser Instance (FBI) is automatically created to access the content. In addition, the automatic FBI system may provide support for novice users with predefined sensitive content sites as well as for more experienced users who can define conflict of interest (COI) classes which allows content from sites in the same user-defined class to coexist in a browser instance.