This document summarizes popular Twitter research in the social sciences. It discusses exemplary research areas like brand communication, crises/disasters, elections/politics, and popular culture. Popular research visions see Twitter as a new data source with insights into human behavior and thoughts. However, there are limitations and challenges. The document reviews the top cited Twitter publications, which applied methods like interviews, experiments, quantitative analysis, and network/linguistic analysis on datasets ranging from thousands to millions of tweets. Challenges include technical limitations, sampling biases, and different approaches to problems like sentiment analysis.