A blog, or web log, refers to a web site or page featuring frequently updated, chronological entries (or posts), such as an online journal or public diary. Blog writers (often called bloggers) may create their blogs for personal or professional use, covering anything from their favorite music to a recent vacation, politics to business developments.

A blog can include words, photos, or both, as well as a unique title, and each post features the date and time it was published. Many blogs also provide a means for readers to post comments about each entry and include archived posts and lists of links to other web sites of interest.