Learn About Social Media Platforms and Privacy

Understanding Major Social Media Platforms and Their Reach

Social media platforms have become central to how billions of people communicate, share information, and connect with others. As of 2024, approximately 5.07 billion people worldwide use social media, which represents about 63% of the global population. The largest platforms include Facebook with nearly 3 billion monthly active users, YouTube with over 2.5 billion users, WhatsApp with 2 billion users, Instagram with 2 billion users, and TikTok with approximately 1.5 billion users. These platforms vary significantly in their primary functions, user demographics, and data collection practices.

Facebook, launched in 2004, operates as a social networking service where users create profiles, share content, and maintain connections with friends and family. The platform generates revenue primarily through targeted advertising, which means user data is a core business asset. YouTube, owned by Google/Alphabet, functions as a video-sharing platform where content creators upload videos and viewers watch, comment, and subscribe to channels. Instagram, also owned by Meta (formerly Facebook), focuses on photo and video sharing with an emphasis on visual content and influencer marketing. WhatsApp provides encrypted messaging services for one-to-one and group conversations. TikTok, a Chinese platform owned by ByteDance, specializes in short-form video content with algorithm-driven recommendations.

Each platform collects different types of information about users based on how the service functions. Understanding what each platform does and how it makes money helps explain what data they collect. For example, platforms that rely on advertising revenue need detailed user information to target ads effectively. Platforms focused on messaging may collect communication content and metadata about who talks to whom and when. The scale of these platforms means that changes in their privacy policies can affect billions of people simultaneously.

Practical takeaway: Before creating an account on any platform, spend time learning what that specific platform does and how it generates revenue. Platforms funded by advertising collect more personal data than platforms that charge subscription fees. Visit each platform's main website or help center to read descriptions of their core functions and business models.

How Social Media Platforms Collect and Use Your Data

Social media platforms collect data through multiple channels, most of which users voluntarily provide when setting up accounts and using services. When you create a profile, you typically provide your name, email address, phone number, date of birth, location, and interests. As you use the platform, the company tracks which content you view, how long you view it, what you like or comment on, who you follow or message, and when you perform these actions. This behavioral data is collected automatically through tracking technologies embedded in the platform's website and applications.

Beyond information you directly share, platforms collect data about your device and internet activity. This includes your device type, operating system, browser type, internet service provider, and IP address. Many platforms use cookies and similar tracking technologies that remain on your device even after you log out, allowing companies to track your activity across other websites. For example, the "Facebook Pixel" is code that Facebook places on millions of websites across the internet. When you visit these websites, Facebook tracks your behavior even if you are not logged into Facebook. According to research from the Pew Research Center, approximately 84% of American adults use at least one social media platform, and the average user has little visibility into the full extent of tracking that occurs.

Social media companies use collected data for multiple purposes. The primary use is targeted advertising—companies use your profile information, browsing history, and interests to show you ads designed to influence your purchasing decisions. Platforms also use data to train artificial intelligence algorithms that determine which content appears in your feed, who to recommend you connect with, and which videos to suggest next. Some platforms share data with third-party advertisers, data brokers, and business partners, though most require these partners to follow data protection agreements. Data can also be sold or shared in response to government requests through legal processes. In 2022, Meta reported receiving 126,000 government requests for user data, affecting approximately 278,000 user accounts.

Practical takeaway: Review your account settings on each social media platform and adjust privacy controls to limit data sharing. Most platforms allow you to restrict who sees your profile, who can contact you, and whether advertisers can use certain data. Look for sections labeled "Privacy Settings," "Data & Privacy," or "Ad Preferences." Document which permissions you grant to each platform's app on your device—many phones and tablets allow you to limit whether apps can access your location, camera, contacts, or photo library.

Privacy Settings and Control Options Available to Users

Each major social media platform provides privacy settings that allow users to control how their information is shared and who can see their content. However, these settings are often complex, distributed across multiple menu locations, and changed frequently by platforms. Facebook offers privacy controls organized into several categories: who can see your profile and posts, who can contact you, who can look you up by email or phone number, and how your information is used for advertising. Instagram provides similar controls but with a different interface design. Both platforms allow you to set your account to "private," which means only people you approve can follow you and see your posts. When an account is public, anyone on the internet can find and view your profile.

TikTok's privacy settings include options to make your account private, control who can comment on your videos, control who can send you messages, and limit how your data is used for recommendations. YouTube allows you to control whether your subscriptions are public or private, whether your watch history is saved, and whether you allow personalized ads. WhatsApp offers end-to-end encryption for all messages by default, but also allows users to control who can see their profile picture, status updates, and "last seen" information—these can be set to visible to everyone, contacts only, or no one. LinkedIn, used for professional networking, provides privacy controls around who can see your profile, your activity, and your connections.

Beyond platform-specific settings, users can take additional steps to protect privacy. Most devices offer privacy settings at the operating system level. On iOS devices, users can prevent apps from accessing location data, contacts, photos, and other sensitive information. On Android devices, similar granular permissions exist. Users can also limit ad tracking on their devices—both iOS and Android offer settings to limit ad personalization. Web browsers offer privacy modes that don't save browsing history and allow users to disable cookies or use browser extensions that block tracking. Many regions have privacy laws requiring platforms to provide data download and deletion options. Under the European Union's General Data Protection Regulation (GDPR), users can request a copy of all data a platform has collected about them, and they can request deletion of their account and associated data.

Practical takeaway: Set aside time to visit each social media platform's privacy or security settings page and implement at least three changes: (1) Set your account to private if that option exists; (2) Restrict who can contact you; (3) Adjust settings for how your data is used in advertising. Write down the email address and password you use for each account in a secure location so you can recover access if needed. Consider enabling two-factor authentication, which requires you to confirm your identity through a second method (like a code sent to your phone) when logging in from a new device.

Understanding Third-Party Data Sharing and Data Brokers

Third-party data sharing occurs when social media platforms share user information with companies outside the platform itself. This practice raises privacy concerns because users may not realize that their data is being shared and used by other companies. Advertisers often want more detailed information than a single platform provides, so they work with data brokers—companies whose business is collecting, aggregating, and selling personal information. When you use a social media platform, that platform may share information with data brokers, who then combine it with data from hundreds of other sources to create detailed profiles about you. These profiles are sold to marketers, financial institutions, insurance companies, and other businesses.

The major data brokers include companies like Acxiom, Experian, and Equifax. Acxiom, for example, maintains data files on approximately 700 million people worldwide. These files typically include information such as age, income level, education, home ownership status, shopping habits, political affiliation, and health interests. When you see an advertisement that seems oddly specific to your situation, it often comes from data that was shared between a social media platform and a data broker. A 2023 report from the Federal Trade Commission found that many data brokers' practices lack transparency and that consumers have limited ways to understand what data is being collected and sold. Some data brokers refuse to disclose their data sources or collection methods, citing proprietary business practices.

Facebook and Instagram have reduced some third-party data sharing in recent years, particularly after the 2018 Cambridge