A wiki is a web platform that enables multiple users to collaboratively create, edit, and arrange content through a browser.

They emphasize simplicity and openness — pages can be created or modified without special technical skills, and most maintain an edit history so revisions can be reviewed or reverted.

Key features
- **Collaborative editing:** Numerous contributors can work on pages, sometimes simultaneously.
- **Edit history:** All edits are stored with timestamps and the author’s name or IP.
- **Interlinking:** Creating links among pages is straightforward, which helps interconnect content.
- **Lightweight markup:** Pages are typically formatted with lightweight markup like WikiText or Markdown.
- **Permission settings:** Access controls vary — from fully open editing to permissions for certain users or groups.
- **Discussion pages:** Dedicated discussion pages enable contributors to coordinate and discuss content.

Frequent uses
- Community knowledge bases such as Wikipedia
- Internal documentation and company knowledge bases
- Collaborative writing and shared note-taking
- Educational and classroom projects

Benefits
- **Fast collaboration:** Many people can collaborate and iterate quickly on content.
- **Openness:** Edit histories and talk pages reveal how content decisions were made.
- **Expandable:** Wikis can grow naturally as contributors add new topics.

Limitations
- **Vandalism and false information:** Public editing can lead to vandalism or incorrect information.
- **Inconsistent quality:** Articles can differ greatly in depth, tone, and reliability.
- **Organizational issues:** Without clear governance, content may become fragmented or disputed.

Illustration
- **Wikipedia** — the largest example, maintained by the Wikimedia Foundation and contributed to by volunteers worldwide.