Blogs are the online equivalent to newspaper or magazine columns. They’re a collection of posts, in order by date, written either by the same person or by a number of people on the same topic. Posts can range from a few hundred words to a few pages, and can be anything from personal journal entries to serious news.
Most companies websites have a blog for the sake of weekly/monthly/annual updates, product announcements, product releases, service changes, industry data or interesting news. The posts are more fleshed out than something on a microblog, but not as formal as a press release.
Blogs come in many different forms, and can be easily added to most websites as a stand-alone section or via a plugin. The most popular these days is WordPress, but other options include Blogger, Blogspot and plugins for Drupal and Joomla.