From the wikipedia on wiki:
A wiki enables documents to be written collectively in a very simple markup language using a web browser. A single page in a wiki is referred to as a “wiki page”, whilst the entire body of pages, which are usually highly interconnected via hyperlinks, is “the wiki”; in effect, a wiki is a very simple, easy-to-use user-maintained database for searching information.
A defining characteristic of wiki technology is the ease with which pages can be created and updated. Generally, there is no review before modifications are accepted.
Wiki might not help you save the world, but it could certainly help you organize your plan to do so 🙂