The Web is a relatively new phenomenon, and has elevated certain problems to a critical level. In this section, the two most prominent problems of Web navigation and Web personalization are discussed, and a short summary of current solutions is presented.
Web Navigation
Because of its large size, dynamic nature and inconsistent structure, the Web is difficult to navigate. “Traditional,” direct navigation approaches depend on an evaluation of the relevance of the currently viewed page as the best indicator of the value of pages pointed to by the current page. This approach relies upon the benevolence of the creator of the link (Kleinberg, 1999), and the hope that by following a series of related links the user will end up at another cluster of useful pages. This “hope” is described as the “small world” phenomenon, which suggests that a highly complex but interacting system will, over time, evolve paths of a limited number of hops between any two related pages.
When the user has discovered a page of lessening interest to them than a previous page, they return backward to an appropriately interesting (although already viewed) page and go forward from a link on that page (if there is one) until all links from that page have been exhausted, retreating back up another level. This navigation strategy is implicitly promoted by the linear nature of Web navigation tools, such as the “back” button of a Web browser.
The traditional strategy closely resembles a depth-first graph search, where leaf nodes are represented by pages of less interest. Effectively, however, the user must go “one page too far” in such a scheme, and travel deeper and deeper distances from the original page they were browsing into possibly uninteresting areas. Due to the highly connective nature of the Web, this suggests that the user will spend more time in distant pages than in pages more closely connected to the original. This, intuitively, is the opposite of the desired result, as pages directly connected to the current page are most likely to be the most relevant pages to it (Lieberman, 1995).