Blog is an online publication of stories with a very high frequency which are presented in reverse chronological order, ie, the last thing that has been published is the first thing displayed.
Quite often a blog have a list of links to other blogs, pages for further information, citing sources or to note that we continue with a theme that started another blog.
They also tend to have a feedback system that allow readers to establish a conversation with the author and each other about what was published.