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.

Common features
- **Collaborative editing:** Several contributors can edit pages, sometimes at the same time.
- **Edit history:** Each change is logged with a time and the editor’s name or IP.
- **Interlinking:** Creating links among pages is straightforward, which helps interconnect content.
- **Lightweight markup:** Simple markup languages (such as WikiText or Markdown) are used to format pages.
- **Permission settings:** Some wikis are open to anyone; others limit edits to registered users or specific groups.
- **Discussion pages:** Talk or discussion pages let contributors debate edits and organization.

Common uses
- Crowd-sourced knowledge resources (e.g., Wikipedia)
- Project docs and corporate knowledge repositories
- Cooperative writing and shared notes
- Classroom and educational projects

Benefits
- **Fast collaboration:** Contributors can rapidly create and improve content.
- **Openness:** Transparency through revision histories and discussions.
- **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:** Content quality may vary widely between pages.
- **Organizational issues:** Poor coordination or governance can cause content fragmentation and disputes.

Notable example
- **Wikipedia** — the best-known wiki, run by the Wikimedia Foundation and built by volunteer contributors worldwide.