How to make a backup of what you've shared on Facebook

Go to "Account Settings"
Choose "Download a copy" of your Facebook data
By the way now the most free cloud services including Blogger (in Blogger you have to go to blogger.com, then pick your blog, then choose Settings / Other, then find link "Export Data", or if you need a copy of your template, then you go to "Template" | "Backup / Restore".

provide opportunity of saving your posts or whatever information you store on those service. I think its a good sign, because by those step they kinda give you freedom and safety to your information: who knows maybe you afraid that datacenters can be destroyed one day due to bankruptcy or other accidents (like accidental demolition, such things happens sometimes, isn't it?)