(n.) Short for Web log, a blog is a Web page that serves as a publicly accessible personal journal for an individual. Typically updated daily, blogs often reflect the personality of the author.
A blog is a personal diary. A daily pulpit. A collaborative space. A political soapbox. A breaking-news outlet. A collection of links. Memos to the world. In simple terms, a blog is a web site, where people write stuff on an ongoing basis. New stuff shows up at the top, so that you can read what's new. Then you can comment on it or link to it or email you.