What is a pillar page and why you need to have one?
A pillar page does the same thing for a website as a pillar does for a house. It is a focal point that strengthens the entire structure. While it was previously the norm in SEO strategy to focus on packing likely Google search terms into articles, a serious failing of that method is that it can create competition with yourself.
UI (user interface) design seeks to make the product as easy to use as possible for the consumer.