One of the most frequently asked questions I hear in these workshops is, "What's the difference between a blog and a wiki"? The terms are often lumped together in discussion of Web 2.0 tools, and the "tinkerer" could find some significant overlap between the two tools, but at their most basic levels, they are intended to serve different purposes.

Answers.com describes the differences as:

Wiki:
  • Multiple authors
  • Edited by a group or team
  • Continuously changing/growing
  • Intended for group communication

Blog:
  • Usually a single author, but can have multiple contributors
  • Author posts, user comments
  • One-to-many communication

The author expounds:

For blogs, the timeline is more important. For wikis, when an article was published matters less, because articles are supposed to be updated as new information becomes available. Blog posts are usually one persons' opinion, followed optionally by comments. Wiki articles represent consensus, but can have an associated discussion/talk page.

The Memphis Public Library has an excellent outline of the similarities and differences between blogs and wikis, but in my opinion, summarizes it very well in this statement:

...as the blog Common Craft states in it's post "Introduction to Stocks and Flows: Weblogs, Wikis, and RSS", a blog is a flow of information. A wiki is a place to stock information. Or look at it another way. In a workplace setting, a blog replaces the bulletin board. A wiki replaces the binder-manuals.

Finally, Portland State University provides some suggested uses for both blogs and wikis:

When you might consider using a blog:
  • To update a site with frequent, individual posts of information or events
  • To host an online journal
  • To provide an up-to-date commentary in a traceable timeline
  • To allow for interactive discussion between original posts & readership

When you might consider using a wiki:
  • To host a database of information that can be accessed and edited by multiple users
  • To promote an environment of information sharing and editing in a community setting
  • To enable individualized information pages about the data being shared ("talk" pages designated for discussion of each wiki page)