Simply go to below the posts, in the center - there are two join options, one for Google/Blogger and the other for Networked blogs.
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Why I Left Your Blog
Keep in mind, I'm no expert and I don't claim to be (seems way too many people online claim to be and what you get is a bunch of generic information you already knew anyway).
This is not blogger only - but for all blog host and websites.
Want to know why I left your blog? Want to know why I won't return?
TWO big reasons.
+If I'm there for a specific post and there wasn't a direct link and I have to hunt for said post. The internet is too full of interesting topics for me to spent 15 minutes trying to find yours. It seems many people participate in something, no direct link, and want to put three or four posts above said "high traffic" post to get views on other posts.
+Your blog took too long to load. Seriously, give up some of the sidebar graphics. I know many authors want to promote every book they've released on the main part of their blog. But, really, chances are, if I came to your blog and it loads, I'm going to stick around and explore for a bit. List your latest couple and have a separate - easy to find - page for all your books.