This document summarizes three research papers on named entity recognition (NER) in tweets. The first paper describes a system called TwiNER that performs NER on targeted Twitter streams to understand user opinions expressed in tweets about organizations. The second paper studies the challenges of NER in tweets due to their terse nature and presents a distantly supervised approach using Labeled LDA that improves NER performance. The third paper proposes modeling user interests in Twitter by extracting named entities from tweets using an unsupervised segmentation approach to avoid large annotation overhead.