I guess I make the assumption that if you are reading this blog then you already know what a blog is and how it might be used or useful in an educational setting. This might not be the case. A blog is a simple publishing tool that allows information to be easily posted to a web page. The tool allows content to be easily created and tagged. If used consistently the tool can allow someone to create a series or flow of information posts about a topic that they are learning about or interested in or have some comment on. This is powerful for both the "blogger" or author of the content and for those who are interested in reading the information over the web. There are many examples of educational blogs on the web. One good place to start when considering K12-related educational blogs is edublogs. The site allows for the free creation of blogs in educational settings.
The "value" proposition for the educational blog is really at many levels. Probably the most profound is the value gained by the individual creating the blog. This allows the content creator to think, reflect, and articulate their thoughts around a given topic or concept.
The next level of value is sharing information over the web. Having knowledgeable people post their thoughts, reflections, and insights allow those looking for information to dig much deeper then "packaged" content or "mass media" provide. These blogs also provide much greater context for peers or affinity groups that have similar interests.
Another level, and the last I'll mention here, is the ability to search an aggregation of like-minded blogs. Consider the power of searching blog posts of 100 second grade teachers how have describe technology integration or classroom management. This becomes the "wisdom of the crowd" and while some ideas will be good and some will be bad, they will all be authentic.
However, to be able to access this type of information, we need to have 100 second grade teachers blog about their classroom activities.
So start blogging!