The remainder of this thesis is divided into three parts, which are structured as follows:
Part II – Background
This part of the thesis provides necessary background material for investigating the problem of using Web data to automatically generate metadata for social media items. We introduce relevant concepts from the following areas:
• Chapter 2 gives a history of online communities and describes the most common forms of social media on the Web. It also introduces the theory of object-centred sociality.
• Chapter 3 reviews different sources of structured data available on the Web, including Web 2.0 APIs, microformat-enhanced data, and Linked Data. It also introduces the fundamentals of the World Wide Web and of the burgeoning Semantic Web. The chapter ends with an overview of existing work on applying Semantic Web technologies to the Social Web.
• Chapter 4 introduces metadata and the various types of metadata that are most relevant for social media items. It also reviews existing meth-ods for generating metadata in online communities – from content-based approaches to more advanced techniques which incorporate additional in-formation from related Web content.
Part III – Core
The Core part of the thesis is composed of the following three chapters which each investigate a different ways of augmenting items in social media with metadata generated from related information on the Web.
• Chapter 5 investigates automatic tag prediction for bookmarked docu-ments, based on anchortext from the Web. The approach is evaluated on a dataset combined from a social bookmarking service and a Web crawl.
Introduction
• Chapter 6 investigates location prediction for social media items, based on language models generated from geotagged social media. The approach is evaluated on a large microblogging dataset.
• Chapter 7 investigates topic classification of social media items, based on hyperlinks to external sources of structured data. The approach is evaluated on datasets from two different forms of social media: a message board and a microblogging service.
Part IV – Conclusion
• Chapter 8 concludes the thesis by summarising of the work presented and explaining how the complementary approaches of Chapters 5, 6 and 7 can be used in combination to improve information-finding in social media.
Potential areas for future research are discussed.
14
Part II
Background
Chapter 2
Online Communities and Social Media ∗
The main contributions of this thesis are methods for enriching social media items with structured metadata in the form of tags, locations and topics. To provide context for the approaches proposed in the core part of this thesis, we begin by introducing relevant background information. The current chapter will provide a brief history of online communities and an outline of the various existing types of social media. Next, Chapter 3 will summarise approaches for expressing Web data, including Social Web data, in a structured, machine-processable way.
Finally, in Chapter 4 we will outline existing approaches to add structure to social media by enriching posts with metadata, covering both manual annotations and automatically generated annotations.
Social media is a term for the wide range of technologies which enable the interaction of groups and individuals on the Web. For many people, they are a fundamental part of daily life, and are often the primary method used to com-municate with family, share media items, research product reviews, and organise protests. The Internet has been used as a means of communication since its in-ception, but it is only in the past decade that it has rapidly become ingrained in our everyday social lives. We begin this chapter with a brief account of the history of online communities, and then describe some of the most prominent forms of social media currently existing on the Web. The chapter finishes with
∗This chapter is partially based on (Kinsella, Breslin, et al., 2008), (Kinsella, Harth, et al., 2008) and (Kinsella et al., 2009)
Online Communities and Social Media
an introduction to object-centred sociality, the theory of objects as mediators of social ties between individuals.
2.1 History of Online Communities
The Internet has long been used as a medium to facilitate social interactions and the formation of virtual communities. Since the 1980’s, Usenet mailing lists allowed people to connect with each other and enabled communities to develop, often around topics of interest. Later, throughout the 1990’s, technologies such as IRC (Internet Relay Chat), instant messaging, Internet forums and blogging continued the trend of using the Internet to build communities. The social net-works formed via these technologies were often not explicitly stated, but were implicitly defined by the interactions of the people involved.
Early social media focused mainly on enabling communication, often between strangers, but with the emergence of social network sites (SNSs) there was a new focus on enabling users to maintain a public profile and a list of connections that can be browsed by others. In 1997, the first website with these features, SixDegrees, was launched. Through the 2000’s, more successful SNSs began to appear such as Friendster (an early SNS previously popular in the US, now widely-used in Asia), LinkedIn (an SNS for professional relationships) and Myspace (a music-oriented service). These services, where explicitly-stated networks of friendship form a core part of the website, have become part of the daily lives of millions of users, and generated huge amounts of investment. In the past decade, the popularity of these sites has grown hugely and continues to do so. boyd and Ellison (2008) summarised the history of social network sites, and suggested that in the early days of SNSs, when only the SixDegrees service existed, there simply were not enough users to generate a critical mass: “While people were already flocking to the Internet, most did not have extended networks of friends who were online”. One report from Miniwatts Marketing Group (2009) shows the growth in the number of Internet users over time. Between 2000 (when SixDegrees shut down) and 2003 (when Friendster became the first successful SNS), the number of Internet users had doubled.
Other forms of social websites have also emerged and the term Social Web has been coined to describe them collectively. Content sharing sites with social
18
Online Communities and Social Media
network functionality such as YouTube (a video-sharing site), Flickr (for sharing images) and Last.fm (a radio and music community site) have achieved immense popularity. Wikis have provided an accessible way of collaborative knowledge management and one example, Wikipedia, has become the world’s largest online encyclopaedia. The Social Web is also strongly associated with Web 2.0, the phase of the Web where websites have become interactive and enable collaboration. Web 2.0 technologies such as RSS (enabling content syndication) and Ajax (enabling interactive webpages) have played an integral role in the development of various Social Web services.
Nowadays, engaging in social media is one of the most common uses of time spent online. A report from comScore, Inc. (2011) states that in 2010, 15.6 per-cent of time spent online globally among those aged 15 and older is accounted for by social network sites. They also report that 90% of U.S. Internet users visited a social network site each month. According to Alexa’s1Web traffic statistics, Face-book was the second most popular website in the world as of July 2011, with the social media services YouTube, Wikipedia, Blogger and Twitter also featuring in the top ten. One of biggest current trends in social media is the growing popular-ity of mobile applications, with smartphones enabling users to remain constantly connected to their social networks. An interesting consequence of mobile usage of social media is the emergence of location-based services. These geosocial services allow users to connect and coordinate with local like-minded people, and to keep abreast of news, events and restaurant reviews in their immediate surroundings.