Wikis are online databases that allow users to add and update content using a web browser. They enable collaboration and knowledge sharing. Organizations use wikis for documentation, building online communities, collaborating with customers, maintaining FAQs and policies. Some advantages of wikis include enabling document uploading and editing, tracking project progress, and accessibility across devices with an internet connection. However, wikis also have disadvantages such as potential disorganization if not properly maintained, learning challenges for new users, and security issues.