To be fair, once your content has been published online, it is ripe for the picking. It is completely frowned upon of course, but you do lose your legal rights the second you click share.
That being said, there are some online tools that can be used to make sure you can put every deterrent in place to make sure your blog remains original and unique and your property only.
If you're closing the stable door after the horse has already bolted and your blog content is already being used elsewhere, there are a few things you can do to get it back, if you think it's worth it.
Copyscape: Copyscape comes highly recommended as a plagiarism checker. As a premium subscriber, you can add the details of your blog site to your account, and they will notify you if your content appears anywhere else online. While this doesn't stop the content from being taken, it does tell you exactly where to contact the blog-owner and ask them to take it down. That's normally enough of a deterrent. While Copyscape can't stop the content from being taken, it can tell you where to find it. They also provide a 'protected by Copyscape' tag which may also be a good deterrent.
Tynt: Tynt gives you a code to add to your website so that every time it's copied and pasted, Tynt will link that text back to your website.
Google Alerts: Google Alerts send an email each time something is published online, and you've asked for a notification. Send them a specific phrase or sentence from your blog and each time it's published, Google will alert you and tell you where to find it.
Wordpress SEO: Wordpress do provide a plugin which lets you add code to your blog feed, this means that if someone tries to use your content elsewhere, a link will be put into their text directing back to your blog site.
Firstly, send a nice email to the website owner advising them that you're the owner of the content and could they please remove it, or reference you in it at least. Sometimes this works and sometimes it doesn't.
If it doesn't, and you want to pursue it further, the Digital Millennium Copyright Act (DMCA) gives the hosting company rights to remove content that is an infringement of someone else's work. Find out who is hosting the blog through WhoIsHostignThis.com and contact the host advising of the situation.
Having your blog content stolen is a tricky one, while it's insulting and upsetting to know that someone has no qualms about copying and pasting something you've spent hours creating; apart from that, is there any real harm if it's not damaging your brand or reputation? These are all personal factors that you need to consider, what do you think? Have you ever had a blog ripped off, and if so what did you do??