The mistake is not understanding that a blog is a website. Blogs are post based structures that provide for and encourage interactive communication. Websites are page based structures that operate as a one-way noticeboards.
A WordPress blog can either be structured as a page based website or its conventional post based blog structure can be retained. That’s why understanding the differences between posts and pages, comprehending the SEO implications of creating a page based structure, and knowing how to use custom menus are key to decision making when selecting a theme, and setting up your WordPress.com blog. http://onecoolsitebloggingtips.com/2010/05/12/better-blogging-at-wordpress-com-pages-and-posts/