In February 2013, during the third quarter of Super Bowl XLVII, a power outage stopped the game for 34 minutes. Oreo, a sandwich cookie company, tweeted during the outage: “Power out? No Problem, You can still dunk it in the dark.” The tweet caught on almost immediately, reaching nearly 15,000 retweets and 20,000 likes on Facebook in less than two days.
A simple tweet diffused into a large population of individuals. It helped the company gain fame with minimum cost in an environment where companies spent as much as $4 million to run a 30-second ad. This is an example of information diffusion. Information diffusion is a field encompassing techniques from a plethora of sciences. In this chapter, discuss methods from fields such as sociology, epidemiology, and ethnography, which can help to social media mining.
Our focus is on techniques that can model information diffusion. Societies provide means for individuals to exchange through various channels. For instance, people share knowledge with their immediate network (friends) or broadcast it via public media (TV, newspapers, etc.) throughout the society. Given this flow of information, different research fields have disparate views of what is an information diffusion process.
We define information diffusion as the process by which a piece of information (knowledge) is spread and reaches individuals through interactions.
The diffusion process involves the following three elements:
- Sender(s). A sender or a small set of senders initiate the information diffusion process.
- Receiver(s). A receiver or a set of receivers receive diffused information. Commonly, the set of receivers is much larger than the set of senders and can overlap with the set of senders.
- Medium. This is the medium through which the diffusion takes place. For example, when a rumor is spreading, the medium can be the personal communication between individuals.
This definition can be generalized to other domains. In a diseasespreading process, the disease is the analog to the information, and infection can be considered a diffusing process. The medium in this case is the air shared by the infecter and the infectee.
An information diffusion can be interrupted. We define the process of interfering with information diffusion INTERVENTION by expediting, delaying, or even stopping diffusion as intervention. Individuals in online social networks are situated in a network where they interact with others. Although this network is at times unavailable or unobservable, the information diffusion process takes place in it. Individuals facilitate information diffusion by making individual decisions that allow information to flow.
For instance, when a rumor is spreading, individuals decide if they are interested in spreading it to their neighbors. They can make this decision either dependently (i.e., depending on the information they receive from others) or independently. When they make dependent decisions, it is important to gauge the level of dependence that individuals have on others.
It could be local dependence, where an individual’s decision is dependent on all of his or her immediate neighbors (friends) or global dependence, where all individuals in the network are observed LOCAL AND before making decisions.