Influencer Engagement Rate Under Scalable Machine Learning Approaches -- Action-Aware Restricted Stream Influence Maximization Model to Identify Social Influencers -- Multimodal Analysis of Client Persuasion in Consulting Interactions: Toward Understanding Successful Consulting -- Advertising on the Web: Soft Narration or Hard Promotion -- The impact of Social Media Marketing on Impulse Buying -- Notes on Advertising Logics in Food Applications -- Studying the Influence of Social Media Use on Sales Performance: the Role of Relational Mediators -- Prediction for Private Brand Items Purchase Behavior of Hair Salons Using Bayesian Survival Analysis -- First Steps in The Entrepreneurial Practice of Marketing -- Customer Visit Prediction Using Purchase Behavior and Tendency -- Verification of Probabilistic Latent Semantic Analysis Clustering Solution Stability and Proposal of Optimal Initial Values Setting Method -- Consumer Attitude and Behavior during Black Friday and Cyber Monday -- The Challenges and Policy Issues Faced by Saudi HEIs when Adopting or Formulating Social Media Policies -- Analyzing the Student eXperience Concept: A Literature Review -- Exploring Factors of an Inclusive Textbook Access Program in Computer Technology Courses -- Online Learning and Student Satisfaction in the Context of the COVID-19 Pandemic -- Activity Comparison of the Participants using Japanese as L2 and their L1 in Group Discussion -- Serious Games in STEM: Online Collaborative Design of a Lunar Simulator -- Safeguarding Academic Integrity in Crisis Induced Environment: A Case Study of Emirati Engineering and IT Students in a Private University in the UAE -- Efficacy of Group Work in the Online Platform: An Exploration of Multicultural Undergraduates' Attitudes in Online Academic Writing Classes -- Design, Implementation and Evaluation of a Technical Platform that Supports Spanish Speaking Children with Intellectual Disabilities Learn English as a Second Language -- Student eXperience in Times of Crisis:A Chilean Case Study -- Social Media During the COVID-19 Pandemic: A Public Health Crisis or a Political Battle? -- The Covid-19 Crisis: an NLP Exploration of the French Twitter Feed (February-May 2020 -- Supporting Students while Shifting to Online Learning During COVID-19: Community College Feedback from Several Computing Courses -- Life Clock: Developing a Technological Platform to Promote Active Ageing -- Layer Zero: An Approach for Deepening Self-Reflection on Instagram Shares -- Role of Social Media in Coping with COVID-19 Stress: Searching for Intergenerational Perspectives -- Gamified Mobile Health Interventions for Mental Well-being of Older Adults -- Pandemic Discussions in VKontakte: Hopes and Fears -- Coaching Older Adults in Health Games: A Goal Oriented Modelling Approach -- Isolation and Use of Social Media by Autistic Individuals during Covid-19 Lockdown: Perceptions of Caregivers -- Infusing Motivation into Reminders for Improving Medication Adherence.

This two-volume set LNCS 12774 and 12775 constitutes the refereed proceedings of the 13th International Conference on Social Computing and Social Media, SCSM 2021, held as part of the 23rd International Conference, HCI International 2021, which took place in July 2021. Due to COVID-19 pandemic the conference was held virtually. The total of 1276 papers and 241 posters included in the 39 HCII 2021 proceedings volumes was carefully reviewed and selected from 5222 submissions. The papers of SCSM 2021, Part I, are organized in topical sections named: Computer Mediated Communication; Social Network Analysis; Experience Design in Social Computing.