Wiki - A Web site which allows users to add and edit content collectively. Wiki stands for "quick" in Hawaiian and is a common form of Web-based collaboration.
Consider this: A free-hosted wiki provider Wetpaint has recently announced it raised a total of $40 million in venture capital. This is a major financial validation of the wiki world that went from being known as a place for teenage starlet fan clubs to winning a reputation as a serious publishing platform.
With more than $63 million spent by enterprises on wikis last year and over $450 million projected by Forrester for 2013, wikis are becoming a very popular, widely-used tool for project management work.
Use a wiki as a personal on-demand notepad with version history, collaborative space for any group projects/discussions, or an organizing tool for research materials.