Developer chatrooms (e.g., the Gitter platform) are gaining popularity as a communication channel among developers. In developer chatrooms, a developer ( asker ) posts questions and other developers ( respondents ) respond to the posted questions. The interaction between askers and respondents results in a discussion thread . Recent studies show that developers use chatrooms to inquire about issues, discuss development ideas, and help each other. However, prior work focuses mainly on analyzing individual messages of a chatroom without analyzing the discussion thread in a chatroom. Developer chatroom discussions are context-sensitive, entangled, and include multiple participants that make it hard to accurately identify threads. Therefore, prior work has limited capability to show the interactions among developers within a chatroom by analyzing only individual messages. In this article, we perform an in-depth analysis of the Gitter platform (i.e., developer chatrooms) by analyzing 6,605,248 messages of 709 chatrooms. To analyze the characteristics of the posted questions and the impact on the response behavior (e.g., whether the posted questions get responses), we propose an approach that identifies discussion threads in chatrooms with high precision (i.e., 0.81 F-score). Our results show that inactive members responded more often and unique questions take longer discussion time than simple questions. We also find that clear and concise questions are more likely to be responded to than poorly written questions. We further manually analyze a randomly selected sample of 384 threads to examine how respondents resolve the raised questions. We observe that more than 80% of the studied threads are resolved. Advanced-level/beginner-level questions along with the edited questions are the mostly resolved questions. Our results can help the project maintainers understand the nature of the discussion threads (e.g., the topic trends). Project maintainers can also benefit from our thread identification approach to spot the common repeated threads and use these threads as frequently asked questions (FAQs) to improve the documentation of their projects.