Q&A software is online software that attempts to answer questions asked by users (Q&A stands for "question and answer"). Q&A software is frequently integrated by large and specialist corporations and tends to be implemented as a community that allows users in similar fields to discuss questions and provide answers to common and specialist questions. There are numerous examples of Q&A software in both open source and SaaS formats, including Qhub, OSQA, Question2Answer, and Stack Exchange. Communities such as Quora or Stack Exchange are closed source Q&A sites.