When writing a blog copyright is an issue. Also when writing a blog fair use is an element you'll need to consider. Learn about them here.
Copyright protects the things you create too. You own the original content you post on your blog. If people copy or steal your intellectual property, you have the right to try to stop them.
The best way to protect your content is to keep an eye out for it elsewhere. These tips can help you tell if your content has shown up on another website or blog:
There are two things you can do if you find your images, text, or other media on another website or blog. First, contact the person who runs the blog or site that took your content. Most blogs list a contact email address, but if you can't find one you can always leave a comment on the offending post. Ask them firmly but politely to remove your content (or give you credit, if you don't mind sharing it). This can work, especially in cases where the other person didn't realize any wrongdoing had occurred.
If contacting the blogger doesn't work, you may want to file a DMCA takedown request. DMCA refers to the Digital Millenium Copyright Act, a law designed to help copyright holders protect their content. Under this law, if a site steals your original content you can complain to that site's service provider. If the service provider finds your complaint valid, it will take down the content.
To learn more about filing a DMCA complaint, read How to Send a DMCA Takedown Notice by Carolyn E. Wright from the blog Black Star Rising.