I am not sure about copyright law, but what I hear is that copyrighting is really quite an uncertain process. It is only as powerful as the provider of the copyright. The important thing to do is arrange that you will be able to win a court case. I think that if you use your full name when becoming an Essay Forum member, and if you post your work here, you can probably use your Essay Forum participation as evidence in court. This is because, when you get a membership, you give your name so that it will be associated with your posts.
You have probably already Googled "copyright" and found services that will sell you a copyright for a fee. These are useful, probably, but nothing is certain. It's all about proving ownership. Post your work here and you will always be able to refer people here to show them that it is your original work. However, for the material you have already posted on your own blog, let your blog serve as proof that you wrote it. Do not post any material to Essay Forum if it appears on other websites.
Kevin, EssayForum.com