A wiki is a content management mechanism for collaborative efforts.  The content is managed by a community of users.  A blog is an interactive medium for disseminating information, links to websites, and other media.  It provides opportunity for discussions on topics selected by the blog administrator.  Blogs tend to have more of a personal viewpoint.  It is easier to have editorial control in a blog.  A wiki is like a website with pages linking to each other.  Wikis can be useful in a variety of settings such as classrooms, group projects, or Knowledge Management repositories.