The term 'Blog' (short for 'Weblog') refers to a type of online (web) journal (log). Blogs are usually made up of a series of individual entries that are ordered chronologically such that the most recent items show up at the top of the page. Blog entries are often written by a single person and the blog software usually provides a mechanism for readers to leave comments on each entry. The Blog itself may contain entries authored by a single person (a personal blog) or contain entries authored by many people (such as a news-magazine).
Blogging tools span a huge range of features and abilities, though they almost all feature chronologically-ordered entries with comments. Many CMS and LMS tools offer support for building blogs. Likewise, many software originally designed for blogging now also support CMS-like or Wiki-like features in addition to the basic blogging support; i.e hierarchically organized pages of non-time-dependent nature.