You probably know by now that Google is taking serious measure to rid it's search engine result pages from duplicated content. It is frustrating to see MFA pages when you are doing your search. These MFA pages used scripts to publish other's articles and blogs. These are duplicate content.
Legitimate Blogs Are Penalized Too
For example, you started a new blog with Blogger.com. You made 3 posts, one everyday. Your main page http://yourblog.blogspot.com lists 3 posts, which is identical to the archive, http://yourblog.blogspot.com/2007_03_01_archive.html, showing the same 3 posts.
To the search engine, this is duplicate content. One of the URLs will be "supplementaled" or worse, delisted from the search engine database.
Blogger Archive Option
To prevent this from happening to your blog. Do you activate the Archive option when you first started the blog. Wait till you've written for more than 1 or 2 months.
The following screen shot shows you how to set Archive Frequency to No Archive.
You can also use the optimized Modified MrMoto template which I modified the Archive page. The modified archive page does not show the entire post but just the title of the post. In this way, your archive page looks different and contains different stuff from your main page. You're safe!