What is a post and what is a page? There are key differences between posts and pages in WordPress. The following is taken from the WordPress support information regarding posts vs pages:
Posts are entries listed in reverse chronological order on the site home page or on the posts page if you have set one in Settings > Reading. If you have created any sticky posts, those will appear before the other posts. Posts can be found in the Archives, Categories, Recent Posts, and other widgets. Posts are also displayed in the RSS feed of the site. You can control how many posts are displayed at a time in the Reading Settings. The URL for a post includes the date the post was published like this: http://dept.camden.rutgers.edu/sitename/2010/11/30/post-title/
If you want your posts to appear on a page other than your home page, read this: Front Page.
See Posts for more detailed information.
Pages are static and are not listed by date. Pages do not use tags or categories. An About page is the classic example. Pages can be displayed in the sidebar using the Pages widget, and some themes display pages in tabs at the top of the blog. If you have 50 pages and you use the Pages widget, then all pages will be listed all the time. The URL for a page looks like this: http://dept.camden.rutgers.edu/sitename/page-title/
See Pages for more detailed information.