Here is how you backup your blog posts if you use the blogger.
1. Bring all posts to one page.
To do this, you have to type the following in the address bar
where 'N' is the Number of posts.
2. Once you bring everything to one page, select all and copy. Paste in a New Word file.
3. Mail the file as attachment to your email account (optional)
Please also have a copy of your blog template, various html codes that you have developed. (example, drop down box, recipe index...)
Send all these files as attachment to your email account and do not forget to date the files.
other techniques of blog backup are written elaborately here