If your blog does not appear on the list of updated blogs on the blog home page, you have your privacy settings to not allow Google or other search engines to spider your blog. All that does is prevent the link from appearing on the updated blog list. Search engines follow links so preventing that one link will hide your blog. However, if you post your blog link anywhere else, they'll find it anyway.
The Tabs at the top of your blog are for the title of your blog first, and then the others are for pages. When you create entries, some are posts and some are pages. Posts would include your daily entries, etc. Pages are specific info pages such as your "About" page. If you create a new entry and select new Page instead of Post, it will show up as a tab at the top.
I hope that helps!