Introduction
Online Social Networks(OSNs) which enables users to build communities based on various grouping structures, common interests and activities have experienced an exponential growth in recent years. It can be considered that online social networks are one of the most remarkable technological phenomena of the 21st century. Most online social networks offer a very attractive means of online interaction between users.

What is an Online Social Network?
An online social network is a Internet service that focuses on building and reflecting of social networks or social relations among people. It fundamentally consists of a representation of a user which is provided through the user profile. The user profile maintains other social links and provides variety of other online services. Among these variety of services that an online social network provides, three basic roles of it can be identified. First, they provide the service to maintain and strengthen existing social relationships and make new relationships. Second, a user can upload his or her own content to the site including personal information, photos, videos etc. Third, it can be used to find new, interesting content by filtering, recommending, and organizing the content uploaded by users.

Mozilla Firefox is a free and open source web browser which is managed by Mozilla foundation. Firefox is based on Gecko layout engine which implements most current web standards. Firefox also support tabbed browsing, spell checking, incremental find, live bookmarking, a download manager, private browsing and location-aware browsing. However even more and functions can be added through extensions created by third-party developers than other web browsers. Therefore in Sri Lanka Firefox dominate as top used web browser today.

Even Firefox is much safer than other browsers, you must note that there are few key points which make Firefox much more safer.