(From "web log") Any kind of diary published on the web, usually written by an individual (a "blogger") but also by corporate bodies.
Blogging is regarded by some as an important social phenomenon as it contributes to the easy exchange of ideas among a large and growing international community ("the blogosphere").
A blog is just a special kind of website. The home page usually shows the most recent article and links to earlier articles, the owner's profile and web logs written by the owner's friends. There is usually a facility for readers to add comments to the bottom of articles. Blogs usually provide an RSS feed of current articles, allowing readers to subscribe by adding the feed to their favourite RSS reader.
Many sites, e.g. http://blogger.com/, let you create a blog for free. Many blogs consist almost entirely of links to other web logs, some publish original content, a few are worth reading.