When you want to add written content to your site, you have two options. You can either create a Page or a Post.
Since WordPress was originally designed as a blogging platform (i.e., to help build websites that were constantly updated with posts about whatever was going on in that blogger’s life), posts were designed for these regular, chronological updates.
WordPress posts are date-dependent and chronological, and this separates them from pages that are date-independent and not really related to any other piece of content on the site.
Pages do not have any defined order, though they can have a hierarchy of parent and child pages.
Posts can be categorized, pages cannot (at least not without plugins).
Another great feature of posts is that they can have Excerpts.
Another important feature of posts is that they appear in your site’s RSS feed.
When to Use Posts and When to Use Pages
The company site uses WordPress “Pages” for all of the main important content that they want to convey to visitors. That includes Homepage, Contact, Privacy, Terms, Testimonials, Services, and Products. These pieces of content are all isolated and unrelated to one another. The data of publishing is not important, so they are date-independent, and they don’t need to be on the company RSS feed.
The company site also has a blog, and in this model, the blog is built with posts. From the point of view of this company, what features of posts make them ideal for the company blog? The fact that posts are chronological? Sure. That means the company can post product updates, with the latest announcements at the top! The fact that these blog posts will end up in the company feed will help spread the news.