Lets start with the very basics. What is a blog anyways? I checked a few sites and here is what they had to say.
Answers.com - To write entries in, add material to, or maintain a weblog.
WikiPedia - A weblog (usually shortened to blog, but occasionally spelled web log) is a web-based publication consisting primarily of periodic articles (normally in reverse chronological order). Although most early weblogs were manually updated, tools to automate the maintenance of such sites made them accessible to a much larger population, and the use of some sort of web application software is now a typical aspect of “blogging”.
Technorati - A weblog, or blog, is a personal journal on the web. Weblogs express as many different subjects and opinions as there are people writing them. Some blogs are highly influential and have enormous readership while others are primarily intended for a close circle of family and friends.
Blo.gs - a weblog (or blog) is a type of web site (or page) that is organized much like a diary or journal — short nuggets of writing added regularly (or not) as a running commentary on almost any subject. other than this time-oriented structure, one weblog may not have all that much in common with the next. to get a better sense of what a weblog is, try clicking through to different weblogs from this site
Ask Jeeves - a shared on-line journal where people can post diary entries about their personal experiences and hobbies
What is all boils down to is a blog is just a website that is easy to create and and edit content. Entries, or posts, happen on a regular basis. That could mean more than one a day or just one every few days. It’s very similar to a diary or a journal only it’s online and shared with everyone on the internet.
Entries are usually short and organized by date with the newest entries showing up first.
Blogs can be whatever you want them to be, much like a website, and they were designed to make it easy for anyone to create content and share with the world.
Still have questions? Post them in the comments and I’ll get back to you. If you can wait, I’ll be posting on topics such as ‘what to blog about?’ and ‘what blog service is good for me?’ in the coming weeks.