The Importance of Page Layout in Web Design
User Expectations:
User's have certain expectations as to the location of elements on page. These expectations come from both print media, such as magazines and newspapers, and now even more so from previous exposure to the Web. In most cases almost anyone viewing your web site has seen at least a few web pages/sites before. The problem can be that if these items aren't were the user expects them to be they may become confused and aggravated and leave the site.
Important Elements to Consider:
The main elements to consider are site navigation, page navigation, section navigation, banners, content, and external links (as a set like a blog roll). Site navigation refers to the element that help you navigate of the top level (and possibly second level) elements of a site. Page navigation refers to elements that help you navigate with in a large page, or one with lots of content. Section navigation is basically all the other types of navigation elements this would include a separate navbar for the individual section (like the one on the left here) or it could be a way to navigate horizontally relatively between sections (like a next or a back), breadcrumbs would fall into this category. Section navigation can be broken down into two types relative and static navigation. The reason we lump them together here is two fold: one they are not always differentiated in the mind of the user (and even when they are it can is often site specific), two while their is a great variety of element that fall into this category their is often not a great variety of them on any one page.
Banners are titles of pages, or ads stuck into pages. They are simply graphics that are not part of the real content of the page. Which brings us to content. Content is the heart of the page, it's what the page is all about, what hopefully the user came there to see. It may include, text, graphics, form elements, etc. but it is the main part of the page. Finally we have on some site a set of external links to other sites, this has been popularized by blogs as blog rolls. But they are seen as a separate element from both navigation and content.
Grouping of Similar Elements:
Users like to see related items near each-other. This correlates with a well know psychological principal of proximity; people view items that are close to each-other as similar. By this it is then easy to infer that similar items on a web page should be grouped near each-other. Thus navigation should be near each-other. External links should be gathered close together. Content elements that relate to each-other should be positioned close to each-other, while those less connected should be in a different location.
Effects on Structure:
There are a few reasons for this; one, there is only so many items you can list in a navbar before it becomes too crowded. Two, there is a limit to how many top level items people will take in. It has been shown in empirical studies that there can be too much depth and not enough breadth, and there can be too much breadth too. In general there should be a good number of top level parts of the hierarchy and never more than 3 levels deep. Three, related content needs to be grouped together both on a page and with in the site structure. If the content on a single page is too varied it can become overwhelming and confusing. Thus related content should be grouped onto a single page or set of pages while content less related should be grouped separately.