activity
20092026
most citedWhat is Gab? A Bastion of Free Speech or an Alt-Right Echo Chamber?

210 citations · 563 across the 27 of their papers we have counts for

collaborators

28 papers

cs.CL2026

SoK: Formal Methods for Fact-Checking and Information Integrity

Nikolaos Kekatos, Theodoros Nestoridis, Charalampos Bratsas +5

An automated fact-checking system returns a label: the claim is true, or it is false. In many such systems the verdict remains the primary output. What is generally missing is a re…

cs.SI2026

Two Fault Lines: Latent Polarity Geometry in X Community Notes

Andreas Andreou, Michael Sirivianos

Community Notes is X's crowdsourced fact-checking system. A note is published beneath the post it corrects only when raters who usually disagree both rate it helpful, a design call…

cs.SI2026

DeTox-Fed: Detecting Toxic Conversations in the Fediverse with Federated Graph Neural Networks

Pantelitsa Leonidou, Nikos Salamanos, Sotiris Gypsiotis +1

The rise of decentralized social networks (DSNs), and in particular the rapid uptake of the Fediverse (e.g., Pleroma, Mastodon, Lemmygrad), introduces new challenges in content mod…

cs.SI2025

Exploring Left-Wing Extremism on the Decentralized Web: An Analysis of Lemmygrad.ml

Utkucan Balci, Michael Sirivianos, Jeremy Blackburn

This study investigates the presence of left-wing extremism on the Lemmygrad.ml instance of the decentralized social media platform Lemmy, from its launch in 2019 up to a month aft…

cs.SI2023★ 1 cited

HyperGraphDis: Leveraging Hypergraphs for Contextual and Social-Based Disinformation Detection

Nikos Salamanos, Pantelitsa Leonidou, Nikolaos Laoutaris +3

In light of the growing impact of disinformation on social, economic, and political landscapes, accurate and efficient identification methods are increasingly critical. This paper…

cs.CL2023★ 3 cited

Identifying Misinformation on YouTube through Transcript Contextual Analysis with Transformer Models

Christos Christodoulou, Nikos Salamanos, Pantelitsa Leonidou +2

Misinformation on YouTube is a significant concern, necessitating robust detection strategies. In this paper, we introduce a novel methodology for video classification, focusing on…

cs.SI2023★ 3 cited

Roll in the Tanks! Measuring Left-wing Extremism on Reddit at Scale

Utkucan Balcı, Michael Sirivianos, Jeremy Blackburn

Social media's role in the spread and evolution of extremism is a focus of intense study. Online extremists have been involved in the dissemination of online hate, mis- and disinfo…

cs.LG2022★ 1 cited

Privacy-Preserving Online Content Moderation: A Federated Learning Use Case

Pantelitsa Leonidou, Nicolas Kourtellis, Nikos Salamanos +1

Users are daily exposed to a large volume of harmful content on various social network platforms. One solution is developing online moderation tools using Machine Learning techniqu…

cs.SI2021

A Unified Graph-Based Approach to Disinformation Detection using Contextual and Semantic Relations

Marius Paraschiv, Nikos Salamanos, Costas Iordanou +2

As recent events have demonstrated, disinformation spread through social networks can have dire political, economic and social consequences. Detecting disinformation must inevitabl…

cs.NI2021

A First Look into the Structural Properties and Resilience of Blockchain Overlays

Aristodemos Paphitis, Nicolas Kourtellis, Michael Sirivianos

Blockchain (BC) systems are highly distributed peer-to-peer networks that offer an alternative to centralized services and promise robustness to coordinated attacks. However, the r…

cs.CY2020★ 2 cited

"It is just a flu": Assessing the Effect of Watch History on YouTube's Pseudoscientific Video Recommendations

Kostantinos Papadamou, Savvas Zannettou, Jeremy Blackburn +3

The role played by YouTube's recommendation algorithm in unwittingly promoting misinformation and conspiracy theories is not entirely understood. Yet, this can have dire real-world…

cs.SI2020

A Privacy-Preserving Architecture for the Protection of Adolescents in Online Social Networks

Markos Charalambous, Petros Papagiannis, Antonis Papasavva +8

Online social networks (OSN) constitute an integral part of people's every day social activity. Specifically, mainstream OSNs such as Twitter, YouTube, and Facebook are especially…

cs.SI2020★ 1 cited

Did State-sponsored Trolls Shape the 2016 US Presidential Election Discourse? Quantifying Influence on Twitter

Nikos Salamanos, Michael J. Jensen, Costas Iordanou +1

It is a widely accepted fact that state-sponsored Twitter accounts operated during the 2016 US presidential election, spreading millions of tweets with misinformation and inflammat…

cs.DB2020★ 8 cited

Hihooi: A Database Replication Middleware for Scaling Transactional Databases Consistently

Michael A. Georgiou, Aristodemos Paphitis, Michael Sirivianos +1

With the advent of the Internet and Internet-connected devices, modern business applications can experience rapid increases as well as variability in transactional workloads. Datab…

cs.CY2020★ 75 cited

"How over is it?" Understanding the Incel Community on YouTube

Kostantinos Papadamou, Savvas Zannettou, Jeremy Blackburn +3

YouTube is by far the largest host of user-generated video content worldwide. Alas, the platform has also come under fire for hosting inappropriate, toxic, and hateful content. One…

cs.SI2019★ 19 cited

On the Influence of Twitter Trolls during the 2016 US Presidential Election

Nikos Salamanos, Michael J. Jensen, Xinlei He +2

It is a widely accepted fact that state-sponsored Twitter accounts operated during the 2016 US presidential election spreading millions of tweets with misinformation and inflammato…

cs.SI2019★ 2 cited

Disturbed YouTube for Kids: Characterizing and Detecting Inappropriate Videos Targeting Young Children

Kostantinos Papadamou, Antonis Papasavva, Savvas Zannettou +5

A large number of the most-subscribed YouTube channels target children of a very young age. Hundreds of toddler-oriented channels on YouTube feature inoffensive, well-produced, and…

cs.CR2018★ 23 cited

Killing the Password and Preserving Privacy with Device-Centric and Attribute-based Authentication

Kostantinos Papadamou, Savvas Zannettou, Bogdan Chifor +9

Current authentication methods on the Web have serious weaknesses. First, services heavily rely on the traditional password paradigm, which diminishes the end-users' security and u…

cs.SI2018★ 46 cited

Who Let The Trolls Out? Towards Understanding State-Sponsored Trolls

Savvas Zannettou, Tristan Caulfield, William Setzer +3

Recent evidence has emerged linking coordinated campaigns by state-sponsored actors to manipulate public opinion on the Web. Campaigns revolving around major political events are e…

cs.SI2018★ 3 cited

On the Origins of Memes by Means of Fringe Web Communities

Savvas Zannettou, Tristan Caulfield, Jeremy Blackburn +4

Internet memes are increasingly used to sway and manipulate public opinion. This prompts the need to study their propagation, evolution, and influence across the Web. In this paper…

cs.SI2018★ 85 cited

The Web of False Information: Rumors, Fake News, Hoaxes, Clickbait, and Various Other Shenanigans

Savvas Zannettou, Michael Sirivianos, Jeremy Blackburn +1

A new era of Information Warfare has arrived. Various actors, including state-sponsored ones, are weaponizing information on Online Social Networks to run false information campaig…

cs.SI2018★ 210 cited

What is Gab? A Bastion of Free Speech or an Alt-Right Echo Chamber?

Savvas Zannettou, Barry Bradlyn, Emiliano De Cristofaro +4

Over the past few years, a number of new "fringe" communities, like 4chan or certain subreddits, have gained traction on the Web at a rapid pace. However, more often than not, litt…

cs.SI2018★ 5 cited

Large Scale Crowdsourcing and Characterization of Twitter Abusive Behavior

Antigoni-Maria Founta, Constantinos Djouvas, Despoina Chatzakou +6

In recent years, offensive, abusive and hateful language, sexism, racism and other types of aggressive and cyberbullying behavior have been manifesting with increased frequency, an…

cs.CY2018

Understanding Web Archiving Services and Their (Mis)Use on Social Media

Savvas Zannettou, Jeremy Blackburn, Emiliano De Cristofaro +2

Web archiving services play an increasingly important role in today's information ecosystem, by ensuring the continuing availability of information, or by deliberately caching cont…