Web logs, or blogs, are simple add-to websites, either with their own domain name, or a subdomain from a blog service provider.
Simple blogs consist of a single front page, with chronological or reverse chronological entries by the blogger, in sequence, usually with an archive of past postings. Links and photos can be added to the text entries. Sidebars contain categories of links and can often also contain photos and graphics. Readers of the blog can add comments to the postings, which will be linked to the message they refer to, or listed on a sidebar.
Blogs also link to other blogs: favorites of the blogger, linked from the sidebar, and blogs that have been recently updated from fellow bloggers using the same host. There are blog directories that will list updated blogs too. One can begin at one blogsite and surf here and there around the web visiting recommended and favorites of the site owners and random ones that have have just been updated.
Blogs range from the simple and banal to classy and complex. A good blogging trek is very satisfying. It's also quite satisfying to publish a blog. They range from personal to completely business.