A blog is traditionally just a website with a selection of recent articles on the main page and links to chronologically-sorted articles in a sidebar. Blog authors and administrators usually create content and manage the site through a web browser instead of a dedicated desktop application.
Programmers of blog software soon discovered that it made sense to add other criteria for sorting, such as tags and categories. Also, some items of content made more sense as hierarchically organized pages. No longer limited to just simple articles with titles, blogs can now even facilitate posting of custom structured content types, such as status updates, asides, FAQs, how-tos, gallery posts, recipes, reviews, video diaries, etc.
If a site calls itself a blog, site visitors expect to have the option to interact with the post authors and/or other site visitors via a comment system.
A site powered by a blog content management system can be indistinguishable from one driven by an enterprise content management system, and the answer to "what's a blog?" becomes more nebulous.
Posted in: Content Management Systems