What is a Blog?

Many people have asked what a blog is? I typed it in Yahoo and this was the response:
A weblog is usually defined as a personal or noncommercial web site that uses a dated log format (usually with the most recent addition at the top of the page) and contains links to other web sites along with commentary about those sites. A weblog is updated frequently and sometimes groups links by specific subjects, such as politics, news, pop culture, or computer issues.

Many people did not know they had the option to post comments. If you click on the comments tab you can share your opinions about the topics being written.