The doctoral study attempts to tackle the growing phenomenon of Internet censorship in the Arab world by taking three aspects of such censorship into consideration: mechanism, impact and circumvention. In the mechanism part, the study relies on a special software designed specifically for the study to collect information about websites reported by the software users as blocked and thereafter verifies the status of censorship of those websites by dynamically comparing traffic data and other data-flow characteristics. Reportedly blocked websites are then categorized into special genres such as political, social, multimedia, etc. and stored in a central database for content analysis to understand which countries block what type of content and through which means and finding inter-dependencies and correlations that could help better understand the relations between different variables. The research also uses an electronic anonymous survey filled by thousands of software users so they could provide their views on if & how censorship impacted their Internet experience and what tools they used to circumvent it. The software that tracks website censorship is also used to circumvent it, providing clues as to how the circumvention process worked in different countries for different users. There is also a qualitative method applied in the study in the form of in-depth semi-structured interviews with a sample of Internet activists producing content on the web in four Arab countries (Egypt, Yemen, Tunisia & Bahrain). The interviews aim at shedding light on what the empirical content analysis does not such as personal experiences, special circumstances and cases describing how censorship and/or circumvention played a role in creating an impact in their work, their environment and their countries.