Someone on LinkedIn was concerned about how to protect his content on his blog and this was my response:
Once you write something, you own the copyright. You can purchase a Copyscape subscription to protect the content on your blog (or website) and that is cheaper than purchasing a copyright on every blog post you write or copyrighting your entire website/ blog. In addition, Copyscape monitors your content and lets you know when someone has taken it. The U.S. Copyright office only "officially" protects it. It is true that without depositing information with the Copyright office, it can be more difficult to protect your claim of ownership.
However, if you are concerned about protecting your content, my question would be - what kind of material are you planning to post?
If your goal is networking, it seems you would want people to share clips from and links to your blog on their blogs back to yours. (Feel free to share my writing on here as long as you let people know where you found it.) It also seems that the type of material you post would be the type of material you want others to share. Any books you publish (and therefore excerpts from them) should be copyrighted upon publication or shortly thereafter (mine are).
If you do find your material is plagiarized (you can self-check with a pay per check option on Copyscape or check you posts free/ with subscription on Plagiarism.com; the subscription to Grammarly.com also comes with a plagiarism checker), you can notify the owner of the website (or if it is another blog, notify the host site) and they have to remove the material. I would also make a MSWord backup of your content because that has a date attached to it. Keep in mind that search engines generally only list the website that first posted the content.
The only content I know of that you never want to post anywhere is screenplay content. The film/television industry is so notorious for stealing work. Screenplays are one of the few items you can have copyrighted before they are complete.