This is perceived as the general term used to refer to the first generation of the World Wide Web. The term is also used to denote the generation of the web existing before the bursting of the ‘dot-com’ bubble in 2001. Lately, the term is often used to describe the web prior to the emergence of blogs, wikis, social networking sites and web-based applications. This generation was developed by Tim Berners-Lee in 1989 and was popularised in 1991 (Berners-Lee, 1998). It is typified by top-down hierarchical information architecture in which users passively consume the content of websites. They use the content and leave it in the same state.

The term ‘Web 2.0’ was coined by O’Reilly Media in 2004 to explain the way in which a new generation of web functions – file sharing, wikis and blogs – differed from earlier web tools. Though original web visionaries including Vannevar Bush, who developed Memex in 1945 and Ted Nelson, who pioneered the hypertext concept in 1963, posited an essentially interactive system, later developers focused more on a linear and one-way approach, hence realising only one facet of the technology. Memex is a concept of an online library that enabled researchers to follow and annotate links which are of interest to them (Cerami, 2003). Ted Nelson coined the term ‘hypertext’ in 1963 to describe a new information management technology he conceptualised. His vision involved implementation of a ‘docuverse’, where all data was stored once, there were no deletions, and all information was accessible by a link from anywhere else (Stewart, 1996). This is the concept now applied by social media tools such as wikis. The earlier web tools – Web 1.0 – were based on the restrictive one-way communication models in which experts presented their material to an audience perceived as expectantly captive. The concept of Web 2.0, on the other hand, espouses the idea that humans are each other’s teachers; that knowledge originates from interactions such as meetings, conversation, dialogue and mentorship; and that even experts have something to learn from their audiences (Alsbjer, 2008). To foster richer user participation, the web has undergone a transition and moved from being a mere collection of websites to a fully-fledged computing platform serving web applications to end users. This transition is what is described as Web 2.0 (O’Reilly, 2005a; Miller, 2006; Maslov, Mikeal and Leggett, 2009). Ultimately, Web 2.0 services are expected to replace desktop computing applications for many functions using newer tools, such as social networking sites, wikis, pervasive communication tools, and folksonomies that emphasise online collaboration and sharing among users (O’Reilly, 2005a). Though the term suggests a new version of the web, it refers not to an update of the Internet or web technical standards, but to changes in the ways they are used.

The term Web 3.0, denoting the notion of the web upon which Library 3.0 is based, was coined in 2006 by John Markoff of the New York Times to describe the third generation of the Internet services that collectively comprise the ‘intelligent web’ (Hendler, 2008; Jastram, 2008). It is generally accepted that Web 3.0 combines the semantic web, Web 2.0 applications and artificial intelligence. Scholars also point out that the concept of the semantic web, which is the foundation of Web 3.0, was originally developed by Tim Berners-Lee (Berners-Lee, 1998; Giustini, 2007). The emergence of Web 3.0 has been influenced by several initiatives seeking to make the web better. Marshall and Shipman (2003) suggest that most of these efforts have been influenced by the need to organise the web which was perceived as being in a state of disorder; maturity of the concept of artificial intelligence; and the desire to transfer the burden of solving the problem of information overload on the web to computers. There are reservations, however, about the actual potential of the semantic web, with some scholars pointing out that some of its goals may not be realistic and may remain just as pipe dreams (Priss, 2002; Marshall and Shipman, 2003).

The concept of Web 4.0 is still under development but Kambil (2008) describes it as the mobile space where users are integrated with the real and virtual objects to create value. He envisions a Web 4.0 environment in which an individual will be able to drive a car which is able to select the shortest traffic-free route by analysing information from a Global Positioning System (GPS). Thus, Web 4.0 will facilitate seamless exchanges of information between human beings and objects that result in appropriate action or intervention. This human-machine collaboration will be achieved through the integration of artificial and human intelligence.

This is the traditional library. It is the oldest and most common library service model. It is the library model that does not apply the web to deliver services. This library model does not apply web technology because it was conceived before the emergence of the web. Library 0.0 spans many generations and has varied greatly in conception and form over the period. Libraries from ancient times, through the classical and medieval periods and into the twenty-first century, have continued to change in response to social needs.

There is little literature on Library 1.0. Many people actually assume that Library 1.0 is the traditional library. This assumption is not accurate because Library 1.0 is the library service model that emerged soon after the emergence of web technology (Web 1.0) in the early 1990s and its application to delivering services (Habib, 2006). Consequently, Library 1.0 can be defined as a library service model utilising the features of Web 1.0 to conceptualise and deliver library services. The majority of the Library 1.0 libraries operated before 2001, when Web 2.0 emerged. It is important to note that even though some Library 1.0 services and products are digitised, a large portion still remain physical and traditional. The Library 1.0 model is the bridge between the past, current and future models of library services.

The term ‘Library 2.0’ was introduced by Michael Casey through his LibraryCrunch blog (available online at http://www.librarycrunch.com), launched in September 2005. In this blog, he expressed his views about the possible benefits of applying the then emerging Web 2.0 ‘to make libraries better’ (Casey and Savastinuk, 2007). This suggestion was made in an effort to relate libraries to Web 2.0 just as had been done for Web 1.0 (Alsbjer, 2008). Discussions about this new concept gained huge momentum, which was replicated in other blogs and websites, and in October 2005 the term was introduced at Internet Librarian 2005 in a speech¹ by Michael Stephens (Casey and Savastinuk, 2007) who used it to refer to the application of Web 2.0 tools in the offering of library services. This conference attracted those information professionals using, developing, and embracing Internet, intranet, and web-based strategies in their roles as information architects and navigators, webmasters and web managers, content evaluators and developers, taxonomists, searchers, community builders, information providers, trainers, guides, and more. Library 2.0 is generally perceived as the application of the interactive, collaborative, and multi-media web-based technologies to library services and collections (Maness, 2006). Though Michael Casey is credited with coining the term, no one person can singly take the credit for the adopted definition or the wave of discussions that popularised it (Crawford, 2006; Casey and Savastinuk, 2007; Cho, 2008).

Belling et al. (2011) explain that the term ‘Library 3.0’ refers to the use of emerging technologies, such as the semantic web, cloud computing, mobile devices, and established tools, such as federated search systems, to facilitate the development, organisation and sharing of user-generated content through seamless collaboration between users, experts and librarians. They add that the main goal of Library 3.0 is to promote and make library collections widely accessible, searchable and usable. They explain further that the end result of Library 3.0 is the expansion of the ‘borderless library’, where collections can be made available readily to library users regardless of their physical location. Critically, they aver that Library 3.0 is a virtual complement to the physical library space, and should ideally work seamlessly within established library systems, services and collections. Though the concept is still evolving, Chauhan (2009a) explains that speed, accuracy, precision and systematic organisation of information available on the web are some of its key elements.

Apart from the above models, Library 4.0, dubbed the ‘aesthetic and emotion-rich’ library, is currently being mooted. It is perceived as a luxurious space for meditation, relaxation and generation of ideas. Schultz (2006) depicts the 4.0 library experience as adding ‘…a new mode, knowledge spa: meditation, relaxation, immersion in a luxury of ideas and thought’:

Many library scholars and practitioners hold the view that the latest ‘point oh’ libraries, currently exemplified by Library 2.0 and Library 3.0, represent an evolutionary change in the way library services are designed and delivered. They argue that, although the use of technology may enhance the speed of library and information service delivery, these uses do not constitute novel approaches. To illustrate this point, Underwood (1990) explains that the use of electronic mail (email), for instance, does not revolutionise message transmission, as the message still arrives at a mailbox, albeit electronically. The essential nature of the service – passing information from source to destination – has not changed. Gray (2006) also argues that technology does not add significant value to the services libraries currently offer. He is supported by Deschamps (2008) who explains that merely having blogs and other social outreach utilities in the new models will not help much if there are active policy and other barriers preventing people from using the library effectively. He further argues that it is communication with patrons that matters and not the mere use of blogs. He concludes that a library can launch many blogs, Flickr accounts and other new media tools and not really accomplish anything when it comes to customer service. Blyberg (2008) agrees with Gray (2006) and Deschamps (2008). He warns that it is easy to become enamoured with social networking sites and new media ‘toys’ to the point where they seem like a panacea for every challenge libraries may currently be facing.

Those who argue that the new models embody revolutionary change reason that though libraries and librarians have continued to evolve over the years in response to ever-changing community needs, the current scenario requires newer strategies, models and tools of service (Courtney, 2007). Vállez and Marcos (2009) explain that the emerging library models entail significant changes at various levels including technology, processes and attitudes, to reduce the barriers users face when accessing information. They suggest that the models represent a significant change in how library services are seen and administered, where concepts such as the usability, interoperability and flexibility of library systems are fundamental. Zheng and Wang (2008) hold a similar view and emphasise that Library 2.0, for instance, is not simply a trivial revamping of traditional library services: rather, it involves deep changes in the management and service ideas, service patterns and system structures, with the purpose of making the library more human, ubiquitous and user-centred.

There is yet another school of thought holding the view that past, current and future changes in library services are neither evolutionary nor revolutionary. The adherents of this school point out that these changes ride on user-centricity, which has always been a basic tenet of library services (Solomon, 2001). Levine (2006) also points out that the new models are a mash-up of traditional library approaches with new concepts. Lawson (2006) explains that the mashing-up is achieved through active conversations between the librarians and users, but it leaves the basic tenets of librarianship intact, even as the tools change.