What is Creative Commons and why would you want to license your blog? For this post we will assume that the posts you are creating for your blog contain only content created by you. This would include using your own pictures, videos and written words. You may want to peruse the Electronic Frontier Foundations page title Legal Guide for Bloggers as well.
The purpose for licensing your blog with a Creative Commons license is that it makes it much easier for others to share, mix and/or use your content. If you aren't thrilled with that, you probably want to stick with the standard copyright license which gives you complete control over the content you create. If you don't change your license it will automatically be considered under the normal copyright.
The reason I license my work online with a Creative Commons copyright license is that I want my work to be used and shared by others. I love the idea that something I created can be inspirational to another teacher or student and that they can build on my ideas and make them better. Instead of having to ask me permission directly, I can give permission through the license which makes it much easier to be used by another.