Evolution of Ego-networks in Social Media with Link Recommendations

Ego-networks are fundamental structures in social graphs, yet the process of their evolution is still widely unexplored. In an online context, a key question is how link recommender systems may skew the growth of these networks, possibly restraining diversity. To shed light on this matter, we analyze the complete temporal evolution of 170M ego-networks extracted from Flickr and Tumblr, comparing links that are created spontaneously with those that have been algorithmically recommended. We find that the evolution of ego-networks is bursty, community-driven, and characterized by subsequent phases of explosive diameter increase, slight shrinking, and stabilization. Recommendations favor popular and well-connected nodes, limiting the diameter expansion. With a matching experiment aimed at detecting causal relationships from observational data, we find that the bias introduced by the recommendations fosters global diversity in the process of neighbor selection. Last, with two link prediction experiments, we show how insights from our analysis can be used to improve the effectiveness of social recommender systems.Comment: Proceedings of the 10th ACM International Conference on Web Search and Data Mining (WSDM 2017), Cambridge, UK. 10 pages, 16 figures, 1 tabl

O riso infeccioso da pestilência: a comédia em tempos de pandemia

Desde Março de 2020, a realidade assumiu, ela própria, contornos de tempos interrompidos. A pandemia da Covid-19 e as vagas de temor por ela causada suspenderam os quotidianos habituais e reconfiguraram formas sociais consolidadas e reconhecidas por todos (Lévy, 2020; Nogueira Pinto, 2020). Embora as pragas e pestes tenham um papel importante nessas redefinições (Defoe, 2001; Manzoni, 2008), este tipo de suspensão (ou alteração) dos modos de vida das comunidades não é causado exclusivamente por motivações sanitárias, como Mackay (2018) bem demonstrou

Analyzing the boundaries of balance theory in evaluating cause-related marketing compatibility

The phenomenon of brands partnering with causes is referred to as cause-related marketing (CRM). This dissertation provides numerous steps forward within the realm of CRM research, as well as balance theory research. Some CRM partnerships may seem less compatible than others, but the level of perceived compatibility (also referred to as “fit”) differs from consumer to consumer. I analyzed CRM compatibility through the lens of balance theory both via a survey-based approach, as well as a social media analytics approach. My contributions to CRM and balance theory are as follows: I found that a consumer’s attitude towards a brand, along with their attitude towards a cause, predicts their perceptions of CRM compatibility. I also show that adding continuous measures of attitude and attitude strength enabled the prediction of balanced and unbalanced consumer evaluations of perceived CRM compatibility. This is the first time that attitude strength has been incorporated into balance theory. I found evidence that a consumer’s attitude towards a brand (or towards a cause), and the strength of that attitude, can spill from one organization to another when brands and causes enter into CRM partnerships. Methodologically, I present a novel way to indirectly measure the strength of attitudes towards brands and towards causes through analyzing perceived conversation topic similarity via a self-reported survey measure, but I was not able to provide evidence that attitude strength could be measured via a social media analytics approach to conversation topic similarity. To dig deeper into this lack of social media analytics results, I provide some considerations with regards to research conducted using a hybridization of a survey-based approach tied to a social media analytics approach. Practically, I share recommendations as to how to choose CRM partners for future CRM partnerships, which should prove beneficial to CRM researchers, practitioners, and advertisers

Topic-Based Clusters in Egocentric Networks on Facebook

Homophily suggests that people tend to befriend others with shared traits, such as similar topical interests or overlapping social circles. We study how people communicate online in term of conversation topics from an egocentric viewpoint using a dataset from Facebook. We find that friends who favor similar topics form topic-based clusters; these clusters have dense connectivities, large growth rates, and little overlap

Diversity and trust in the newsroom : examining the role of homophily on establishing trust using ERGM

This dissertation focuses on the trust relationship in the newsroom to examine journalists’ status-based homophily, which refers to an individual’s tendency that similarity in social statuses breeds informal connection at work. It analyzes South Korean newspapers as a case study because their newsroom composition has become diverse and intergroup relationships emerged as a key issue for newsroom management. Trust at work serve facilitates knowledge, information, and the skill set relevant to organizational survival. However, trust is not shared by everyone because status-based homophily governs the informal relationship. In particular, separated informal relationships between the majority with power and control and minority groups lead to the following research question of “which social characteristics of individuals that represent a symbol of social statuses at work generate homophily in journalists’ trust?” To answer this research question, the author incorporated network homophily and social identity theory as main theoretical frameworks and employed inferential network analysis with the Exponential Random Graph Model (ERGM) as a primary methodological approach. Considering the unique nature of local characteristics in South Korea, the author assesses five social statuses on South Korean journalists’ homophilous tendency in their trust network: (1) gender, (2) tenure, (3) academic prestige (4) recruitment, and (5) competence. In particular, a separate empirical analysis on two cases of the South Korean newspapers verifies whether status-based homophily is consistently found across the newspapers with different cultures and organizational composition. The inferential network analysis of ERGM identified tenure-based homophily for both newspapers, while recruitment-based homophily and competence-based homophily were only found in one of the newspapers. Gender-based homophily became statistically insignificant as additional status-based homophily terms were added, which shows its relative weakness in determining journalists’ homophilous tendency compared to other status-based homophily terms. Academic prestige-based homophily was not found to be significant for both newspapers. This dissertation will add more insight into the theoretical adaptation of the social network theory and its association with the journalism practice inside the newsroom. Primarily, newsroom managers will learn a practical implication of how to manage the growing diversity inside the newsroom to unlock the positive effect of diversity.Journalis