Blogs — short for Weblogs — are online forums that allow writers to present their opinions, observations, and reflections to a broad readership. They can consist of the contributions of a single writer, or they can draw on contributions from multiple writers. Blogs can be published and maintained by individuals, in a manner similar to putting material on a personal Web site. They can also be sponsored by news organizations, public interest groups, government agencies, corporations, and other organizations. When a blog is sponsored by an organization or a publication, the writer takes into account the purpose of the organization or publication and the interests, needs, and backgrounds of readers who visit the blog.

Blogs are frequently used in analytical and informative writing. Entries typically are brief and often present a personal perspective on an issue. However, because blogs have fewer length limitations than a newspaper, magazine, or journal article might have, blog entries are more likely to rely on evidence from other sources than are opinion columns and letters to the editor. Because of their electronic format, they can also use multimedia illustrations, such as video and audio clips or interactive polls, and link to other sources. And because readers can reply publicly to a blog entry by posting responses and analyses of their own, conversations can be extended over time and can involve readers and writers more actively.