Social anxiety is "an intense, persistent fear of being scruitinzed and negatively evaluated by others in social or performance situations."
According to the Anxiety and Depression Association of America (ADAA), 15 million adults in the United States suffer from social anxiety, avoiding situations or face-to-face contact because of their fear of doing something that would cause them embarrassment.
For some, the internet has become their life-line. It gives them a chance to interact with others, meet new people and maintain relationships, all without having to leave their home or meet with their friends face-to-face. But there is also a downside to this. Some studies have shown that those with social anxiety have a higher risk of developing "internet addiction."
Advantages of Social Media and the Internet for Those with Social Anxiety
One Facebook member, Josh Chiles, told the Washington Post, "There is no doubt that Facebook has improved my life in building relationships with other people." 
There have been several studies looking at the relationship between online networks and social anxiety. These studies give us mixed answers. One study concluded, "Although the Internet does not change a person's actual level of social anxiety, it may decrease their perception of social anxiety when interacting online." 
Other research has shown that those with social anxiety may find "it easier to interact online where anonymity can be maintained rather than engage in face to face interaction where being observed by others might induce a fear." 
Social websites, such as Facebook, give a way to practice social skills - in a non-threatening environment. Those with social anxiety also have a hard time knowing what to talk about or initiating conversations. Friending acquaintances and learning about their likes, their dislikes and their hobbies provide a starting point for conversation. It also gives you a chance to find commonalities. One woman told the Washington Post that Facebook helped her to make connections and start conversations more easily in her workplace, "You can see what they like and that helps you approach them. It facilitates a conversation."  Another Facebook user stated, "I think Facebook has really enhanced my life. It allows me to connect with people I wouldn't connect with otherwise." 
Disadvantages of Social Media and Online Interactions
According to several studies, those with social anxiety are more likely to use the internet as a crutch and to have "problematic internet use" or the inability to control, reduce or stop online behavior. According to one study, "Internet addiction among those with social anxiety disorder has been associated with personal, relational and occupational difficulties directly and might even worsen the individual's social anxiety in general." 
Whether using social network sites help or hinder depends on the individual. However, even when it helps, it does not address the underlying issue of social anxiety. Treatment for that is still needed.
   "Can Facebook Help Overcome Shyness," 2011, Feb 12, Michael Rosenwald, Washington Post
"College Dating and Social Anxiety: Using the Internet as a Means of Connecting to Others," 2077, Sarah B. Stevens and Tracy L. Morris, CyberPsychology and Behavior
 "Internet Usage Among College Students and Its Impact on Depression, Social Anxiety and Social Engagement," 2010, Kimberlee D. DeRushia, Indiana University of Pennsylvania
 "Problematic Internet Use Among Persons with Social Anxiety Disorder," 2012, Hillary Greene, Andrew Kukes Foundation for Social Anxiety.
 "Reasons for Internet Use and Social Anxiety," 2005, Robin-Marie Shepherd and Robert J. Edelman, Personality and Individual Differences