DESIGN GUIDELINES
The Rise of the Sub-SiteWeb users need structure to make sense of the many and varied information spaces they navigate. The fundamental nature of the Web does not support any structure beyond the individual page which is the only recognized unit of information.
Single pages are obviously not sufficient as a structuring mechanism, and from the early days of the Web, we have advocated an emphasis on the site as an additional fundamental stucturing unit. Since a single click can take the user to the other end of the world, every page needs to provide users with a sense of place and tell them where they have landed. A recommended standard is to put a corporate or organizational logo in the upper left corner of the screen (upper right corner in countries using a right-to-left language). When clicked, this logo should take the user to the main home page for the site.
Explicit recognition of the site as a structuring mechanism is important for Web usability, but most websites are much too large for the site level to provide the only structure. Much information can be hierarchically organized, and an explicit representation of the hierarchy can be added to the top of the page to provide additional context and navigation options. For example, the intranet for the hypothetical BigCo company might have the following list of the nested hierarchy leading to the home page for the Stockholm office:
BigCoWeb -> Sales -> European Region -> Sweden -> Stockholm OfficeEach of the elements in the hierarchy list should be made a hyperlink to the appropriate top page for that level of the hierarchy. Note that the name of the lowest level of the hierarchy (here, "Stockholm Office") should not be a link when displayed on the top page for that level. Even the lowest-level name should be made active when displayed on a leaf page on that level.
For information spaces that cannot easily be hierarchically structured, the sub-site can be used as a helpful additional structuring mechanism. Sub-sites can also be used in hierarchical information spaces to give particular prominence to a certain level of the hierarchy which is used as the sub-site designator.
By "sub-site", simply means a collection of Web pages within a larger site that have been given a common style and a shared navigation mechanism. This collection of pages can be a flat space or it can have some internal structure, but in any case it should probably have a single page that can be designated the home page of the sub-site. Each of the pages within the sub-site should have a link pointing back to the sub-site home page as well as a link to the home page for the entire site. Also, the sub-site should have global navigation options (e.g., to the site home page and to a site-wide search) in addition to its local navigation.
Sub-sites are a way of handling the complexity of large websites with thousands or even hundred of thousands of pages: By giving a more local structure to a corner of the information space, a sub-site can help users feel welcome in the part of a site that is of most importance to them. Also, a large site will often contain heterogeneous information that cannot all be squeezed into a single standard structure, so the ability to have sub-sites with somewhat different look-and-feel can provide an improved user experience. A sub-site is a home environment for a specific class of users or a specific type of usage within a larger and more general site.
There is a tension between the desire of the sub-site designer to optimize fully for the specific needs of local information versus the need for consistency across the entire site. Sub-sites should definitely not aspire to become independent sites with no relation to the parent site of which they are part and which should provide them with context and richness. In my opinion, IBM's new AlphaWorks sub-site is an example of what not to do: IBM has maintained a strong site identity across all their other sub-sites with a logo in the upper left corner and a tilted sub-site image in the upper right, but AlphaWorks hides the logo at the lower left and has an inconsistent style. It's almost as if AlphaWorks was ashamed of its parent site.
A good example of a sub-site done right is ZD Net's AnchorDesk. AnchorDesk provides a platform for the respected computer industry commentator Jesse Berst to discuss current events in computing and pull together recommended links to additional information from across the rest of the Ziff-Davis site. The AnchorDesk sub-site uses human editing as a guide to an otherwise overwhelming information space and has value-added use of hyperlinks to provide the foundation for the commentary.
In Defense of Print
As an online publishing enthusiast, I sometimes get ridiculed for having written a traditional printed book about hypertext and the Internet. It is an unfortunate fact that current computer screens lead to a reading speed that is approximately 25% slower than reading from paper. We have invented better screens and it is just a matter of time before reading from computers is as good as reading from paper, but for the time being we have to design our information for the actual screens in use around the world.
The reduced reading speed on computers can be compensated by good hypertext design that allows the user to read less information and to find it faster. A typical example is online help and documentation: because the information is right there on the computer, there is no need to spend time finding the hardcopy manual, and because of good search tools and hypertext links between related information, users can go directly to the one or two sections that contain the answer to their problem. After all, Nielsen's first law of computer documentation is that users don't read it. The second law is that if they read it anyway, it's because they are in deep trouble and need the answer to a specific problem. Thus, somebody reading a manual won't really read it cover-to-cover, so online presentation makes perfect sense.
Other types of information do require the user to read large amounts of text. A typical example would be the instructional materials to teach a programmer a new programming language. Users typically want to spend an extended period of time reading long texts and they prefer not having to sit at their screen while doing so. Thus, even when the reading speed problem gets solved, we may still find that people decide to print out long texts rather than read them on the screen.
In any case, our surveys have shown over and over again that users do like the ability to get long documents in hardcopy, which is why even online publishing systems need a print feature. The implication for web design is to provide printable versions of any long documents. Web browsers are slowly gaining decent print functionality, but one cannot rely on browser companies to produce well-crafted printouts since their main interest is online information. For example, Netscape and Internet Explorer both use the same typeface and font size for online viewing and printing, even though it is known to all typography specialists that the two media require different type.
My recommendation is to generate two version of all long web documents: one that is optimized for online viewing (is chunked appropriately into many files and has plenty of hypertext links) and one that is optimized for printing (has good layout and is in one piece). The print file should probably be in formats like PostScript or PDF. It is extremely important to denote any such files as being for printouts only and always supplement them with links to the same content in HTML for online viewing by users who want to browse or search a small part of the document.
PostScript and Acrobat files should never be read online. PostScript viewers are fine for checking out the structure of a document in order to determine whether to print it, but users should not be tricked into the painful experience of actually spending an extended period of time with online PostScript. We learned this lesson the hard way in one of my projects: The current release of Sun's AnswerBook documentation viewer displays PostScript windows of the same pages that are used in our printed manuals. The next version of the product will use an SGML-based content structure that allows for much nicer information presentation and searching. All our user tests of the pre-release version show tremendously enhanced user performance and satisfaction with the new product, so you have something to look forward to if you are a Sun customer.
