# Effective Techniques for Protecting the Privacy of Web Users
## 3 Background
### Privacy Protection Tools (PP-Tools)  
As part of the huge number of online advertisements that are intrusive and annoying, the market is responding to the users' disapproval against them. Several studies have shown that 78% of internet users dislike advertising on websites [15; 16]. That is because they are concerned about the invasion of privacy through online tracking, which is reflected in the rapid growth of ad-blocking tools (Extensions for Chrome and Add-ons for Firefox). They are also called privacy protection tools (PP-Tools). Throughout the years, these tools have been used for a variety of purposes including hiding advertising content or detecting and preventing web tracking techniques on web pages to ensure users' privacy. Many of the privacy protection tools are controlling the execution of JavaScript programs and have much more access to the system features and browsers as JavaScript is embedded within web pages. The advantage of using these tools is that they provide flexibility for users so that removing or installing them can be done easily. However, still cannot achieve the balance between blocking tracking and accepting functional JavaScript programs. Here we briefly describe and evaluate the most common privacy protection tools (PP-Tools) considered in our experimental analysis study. Table 1 describes the number of users, filtering rules, and statistics of privacy protection tools. * Disconnect(DC): [17] Is a blacklist-based technique primarily used to block 3 rd-party tracking cookies and JavaScript programs that are used on social networks like YouTube, Facebook, Instagram, or Twitter. It also provides a Premium version to protect VPN networks and detect malicious software. * Ghostery(GT): [18] Is a powerful privacy extension or add-on launched in 2009 that can detect and block tracking scripts and cookies from webpages in order to improve privacy and focus on only important content. Moreover, it scans the DOM tree with regular expressions for Advertisements, tracking, and other entities stored in a predefined blacklist. As a further feature, the users are given the option to enable trackingdo-mains manually with this tool. Therefore, users can activate or deactivate any third-party services within different categories such as Social Media Widgets, Analytics Services, Ads, and so on. * Adblock Plus (ABP): [19] Is primarily focused on blocking unwanted online content including advertisements, banners, pop-ups, videos, and other forms of advertising that are disruptive and bothersome, as well as preventing malware and tracking. It relies on blacklists with a large number of community-maintained rules. Blacklists can be customized to suit the user's needs, such as EasyList (The most popular one that blocks ads from English sites), Fanboy's list (The second most popular Adblock Plus filter list), FR List (which Blocks ads from French sites), or AR List (which Blocks ads from Arabic sites). It also works by searching HTML rendered pages (DOM trees) with regular expressions and blocks the downloading of web resources that refer to blacklisted advertisements and trackers. * uBlock (UB): [20] It is an open-source browser extension for blocking ads and filtering content. It works with most web browsers including Firefox, Chrome, Chromium, Opera, and some versions of Safari. According to some reports [21], uBlock is considered less memory-consuming than any other extension that offers similar functionality. It uses the same lists of the previous extensions including EasyList, Peter Lowe, Malware Domains, EasyPrivacy, etc. As well as users can set their own filtering preferences. * Privacy Badger(PB): [22] It uses an internal blacklist and a heuristic algorithm to block different types of third-party tracking, including canvas fingerprinting, local storage super cookies, and identifying cookies. In comparison to other PPTs, PB does not require any prior knowledge, configurations, or setup on the user's part.