If I’m doing regular blog posts for a client, I set them up with a free account at MyFreeCopyright.com. This service uses the RSS feed from the blog to digitally file a copy of each post with a unique time-stamped identity. The blog owner will receive an email each time a post is protected.
While this doesn’t keep someone from stealing your content, it does create definite proof of first publication, and you can place their logo on your site to discourage copying of your content as well.
Please request this service if you want it, as there are many opinions about copyright and allowing others to use material from a blog.