Blogger.com, the host of this site, defines a blog as:
"A blog is a personal diary. A daily pulpit. A collaborative space.
A political soapbox. A breaking-news outlet. A collection of links.
Your own private thoughts. Memos to the world. Your blog is whatever you want it to be. There are millions of them, in all shapes and sizes, and there are no real rules.In simple terms, a blog is a web site, where you write stuff on an ongoing basis. New stuff shows up at the top, so your visitors can read what's new. Then they comment on it or link to it or email you. Or not." source
Wiktionary defines the word blog as:
"A personal or corporate website in the form of an online journal, with new entries appearing in sequence as they are written, especially as dealing with reflections or opinion, and typically incorporating links to other articles."
Wikipedia defines a blog in a similar way, and includes useful information regarding the history and evolution of blogging.
Here is another comprehensive definition of a Blog from an avid blogger:
"Most blogs are primarily text based. However, increasingly popular are video blogs (vlogs), and photoblogs, which offer potentially more interactive ways to share content than via mere text alone."
As this blog tries to demonstrate, all of the different media elements can easily coexist in a single blog. Posts can be categorized, and are automatically archived by the blogging program. Thus they are easily referred to in the future, and accessible via labels.
Posts can be e-mailed to a dedicated e-mail address which automatically publishes the e-mail's content on the blog. Individuals interested in the specific content of the blog also have the option to subscribe to the blog and receive updates whenever new posts are published.
What are blogs typically used for?
Blogs are commonly used by individuals as a type of on-line journal in which ideas, social commentary, or anything else are shared. These can either be focused on a specific theme, or dedicated to whatever random string of topics the blogger wishes to share. A typical theme for blogs is politics / political commentary. Increasingly, blogs are finding a function in the realms of education and organizational communication as well.