Podcasts or vodcasts are audio or video digital media files that can be downloaded from the Internet. In December 2020, there were 41.9 million podcasts according to Apple [9]. As of 2023, there are more than 4 million podcasts registered around the world [9]. According to the Pew Research Center, 64% of Americans have ever listened to a podcast, which is a dramatic increase compared with 2006 (11%) [98]. Generally, men download podcasts more often than their female counterparts, and adults 18 to 49 years of age are the most likely of all age-groups to have downloaded a podcast [6].

Social networking sites include Facebook, Instagram, Snapchat, X (formerly Twitter), TikTok, and LinkedIn. In 2021, 69% of Americans 18 years of age and older used Facebook, 81% used YouTube; 40% used Instagram (a Facebook company), 31% used Pinterest, 28% used LinkedIn, and 23% used Twitter [97]. This is astounding considering that only 38% of Internet users were social networking in 2005 [10].

Before discussing how Internet technologies have been and may be used in the health and mental health fields, it is vital to have a clear understanding of the terms. Web 1.0 revolved around static pages, with little or no user interaction, essentially making the Internet "read only." Personal websites, Internet directories, online (static) encyclopedias, Internet browsing, and taxonomies are examples of Web 1.0 [24,25]. Meanwhile, Web 2.0 is considered user-centric, because it promotes group interaction, collaboration, community, conversations, networking, and connections [24,107]. Web 2.0 has been coined the "social web" because it is much more interactive than Web 1.0. Examples of Web 2.0 applications include [2,24,26,27,107,108]:

The differences between Web 1.0 and Web 2.0 become clear when considering the example of online encyclopedias. Under the Web 1.0 application, individuals would search for information in a static online encyclopedia. In the Web 2.0 generation, individuals not only search for information in online encyclopedias, but can create and edit entries (as with Wikipedia) [28]. Web 2.0 is characterized by an active audience, with multidirectional and participatory communication [79]. Again, there are benefits and drawbacks of both.

In Web 3.0, the Internet is viewed as a database with intelligent search capabilities [4]. This could involve moving beyond the sharing of information to the comparing of data in meaningful ways. The relationships between ideas or information would become more important. For example, uploaded photographs might exist on a calendar platform that also displays activities or appointments for that day, giving some insight into what the individual was doing when the photograph was taken. However, it is unclear when or if this will become the dominant force in Internet technology.

The definition of Health 2.0 has been nebulous and there is no clear roadmap [136,137]. Some have categorized Health 2.0 under the broader category of digital health. Others have defined Health 2.0 simply as, "the use of social software and its ability to promote collaboration between patients, caregivers, medical professionals, and other stakeholders in health" [25]. Some have described it as health care with the addition of social media [163]. The end result is health care that is participatory and takes place constantly, rather than a series of episodic events. The hope is that this enhancement of the healthcare experience will allow the provider to foster a team approach to care instead of an expert/novice relationship [29]. Consumers of health services use Web 2.0 applications not only to find health information but to develop communities to support one another, share experiences and information with one another, and evaluate physicians and healthcare providers [2,110]. It is used by patients but also by healthcare and mental health professionals [137]. Examples include [2; 31; 32; 80; 110; 111; 137; 163; 164]:

The use of Web 2.0 applications can affect professional relationships and boundaries between providers and patients/clients. However, professional organizations and ethics committees have been slow to establish rules for interacting with patients/clients online. In a 2021 systematic review, the blurring of professional boundaries, behavior, and values surfaced as a prominent theme in a meta-analysis of 44 articles assessing the use of social media among healthcare professionals and students [174]. In these articles, breaches of confidentiality, promotion of pharmaceutical products, derogatory remarks regarding other professionals, and profanity and sexually explicit misconduct were noted. In some cases, healthcare professionals published photos and information that violated their patients' confidentiality and privacy. Only 5% obtained formal consent from patients prior to posting information or photos [174]. In a survey of psychologists, social workers, and physicians, 59% of practitioners indicated they maintained a Facebook account and 75% of these users reported using a privacy setting [89]. In another study, 77% of psychologists indicated they had an account on a social networking site, and of these users, 85% used privacy settings [36]. However, practitioners were unclear about what to do when clients contacted them through a social networking site. On the surface, it appears to be an innocuous request, but it may allow the client access to personal information and interactions that may fall outside established professional boundaries and create dual relationships [90,150]. If the practitioner does not accept the request or ignores the contact, the client might misconstrue this as rejection. In addition, professionals' behaviors on social networking sites (e.g., posted pictures, interactions with friends) could inadvertently have a negative effect on the integrity of the profession [90,91]. Therefore, there is a blurring of private and public spaces [119]. Unfortunately, there appears to be minimal guidelines in the literature about digital professionalism [174].

In order for patients to obtain health information online, many skills are needed. At the most basic level, technical skills related to the use of a computer (operations) and Internet searching (navigation) are required in order to effectively access the Web [94]. A higher level of proficiency, including cognitive critical thinking skills, is necessary in order to evaluate the tremendous amount of information retrieved and to choose the most relevant and valid recommendations.

However, health literacy is not merely about being able to read the information but includes social components and the creation of meaning [58]. Informational competence, for example, involves appropriately evaluating the validity and authority of health information. Autonomous competence, the ability not only to evaluate the information but also apply it within the context of one's life, is also a part of health literacy [58]. Health literacy also includes an individual's ability to navigate the health system, communicate with their providers, follow prescribed treatment plans, and evaluate health information and evidence [95]. Health literacy can be organized into three categories [125]:

In an observational study of online search behaviors for health information, researchers found that participants tended to rely on what information they could locate rapidly rather than searching for more credible sources, relying mainly on information found on search engines such as Yahoo or Google [66]. They will not often verify the information. The majority of the participants also relied on the first five search results to obtain the information. Other research has found that participants tend to judge results of health information searches based on position or rank or based on other users' comments [121]. This speaks to the necessity for practitioners to educate consumers regarding the importance of gaining informational and autonomous competency [58].