Social media are indispensable elements of social big data applications. In
this chapter, we will ﬁ rst classify social media into several categories and
explain the features of each category in order to better understand what
social media are. Then we will select important media categories from a
viewpoint of analysis required for social big data applications, address
representative social media included in each category, and describe the
characteristics of the social media, focusing on the statistics, structures, and
interactions of social media as well as the relationships with other similar
1.1 What are Social Media?
Generally, a social media site consists of an information system as its
platform and its users on the Web. The system enables the user to perform
direct interactions with it. The user is identiﬁ ed by the system along
with other users as well. Two or more users constitute explicit or implicit
communities, that is, social networks. The user in social media is generally
called an actor in the context of social network analysis. By participating in
the social network as well as directly interacting with the system, the user
can enjoy services provided by the social media site.
More speciﬁ cally, social media can be classiﬁ ed into the following
categories based on the service contents.
• Blogging: Services in this category enable the user to publish
explanations, sentiments, evaluations, actions, and ideas about certain
topics including personal or social events in a text in the style of a diary.
• Micro blogging: The user describes a certain topic frequently in shorter
texts in micro blogging. For example, a tweet, an article of Twitter,
consists of at most 140 characters.
2 Social Big Data Mining
• SNS (Social Network Service): Services in this category literally support
creating social networks among users.
• Sharing service: Services in this category enable the user to share movies,
audios, photographs, and bookmarks.
• Video communication: The users can hold a meeting and chat with other
users using live videos as services in this category.
• Social search: Services in this category enable the user to reﬂ ect the
likings and opinions of current search results in the subsequent
searches. Other services allow not only experts but also users to directly
reply to queries.
• Social news: Through services in this category the user can contribute
news as a primary source and can also re-post and evaluate favorite
news items which have already been posted.
• Social gaming: Services in this category enable the user to play games
with other users connected by SNS.
• Crowd sourcing: Through services in this category, the user can outsource
a part or all of his work to outside users who are capable of doing the
• Collaboration: Services in this category support cooperative work among
users and they enable the users to publish a result of the cooperative
1.2 Representative Social Media
In consideration of user volumes and the social impact of media in the present
circumstances, micro blogging, SNS, movie sharing, photograph sharing,
and collaboration are important categories of social big data applications,
where social media data are analyzed and the results are utilized as one of
big data sources. The proﬁ les (i.e., features) of representative social media
in each category will be explained as well as generic Web, paying attention
to the following aspects which are effective for analysis:
• Category and foundation
• Data structures
• Main interactions
• Comparison with similar media
(1) Category and foundation
Twitter [Twitter 2014] [Twitter-Wikipedia 2014] is one of the platform
services for micro blogging founded by Jack Dorsey in 2005 (see Fig. 1.1).