Wikis are much more about collaboration with a set group of people towards an end goal, or a means. It is very unified and created to serve a purpose and access is generally only given to people who are considered part of a team or serve the general purpose of the Wiki. A blog is (usually) only written and maintained by a single person and the audience it is given to is essentially the entire internet. Anyone and everyone can stumble upon a blog and start reading. Blogs don't necessarily have to have a purpose, either. Many people just ramble or use it as a type of journal. Other people actually make their lively-hood off of blogs and generate passive income through programs like Google AdSense or Affiliate Marketing.
That's probably the one area in which Wikis have not been really used for, which is generating income. Every so often the people who own and run Wikipedia actually put up a message asking for donations to help keep Wikipedia running since it is not funded by any particular corporation and does not generate income on its own. If Wikipedia could work like a blog could and make money through ads and back linking and such, it would be able so sustain itself but it would also become a VERY different website. Being sponsored by corporations could lead the information available on Wikipedia to be affected in a way that is skewed in favor to the companies that fund them, which would then lead to the info on Wikipedia being much more unreliable than it is now. Probably one that people would not feel compelled to use, really. So it is most likely best that Wikipedia remain reliant on the donations of generous people.
Works Cited:
1.) Wikis at work: Up from the grassroots by Rob Edmonds E.learning Age; Oct 2006; p. 14
2.) "What motivates WIKIPEDIANS?" by Oded Nov, Communications of the ACM; Nov2007, Vol. 50 Issue 11, p60-64.
