Web interaction design is not only a means of making sites more useable. It can also be used for facilitating cross- and up-selling. Amazon is one of the best examples with their recommendations and product combos at special prices.
UIE experienced from web-site usability testing that users won't be lured away until they've accomplished some or their entire goal:
"The seducible moment can happen only when users have completed at least part of their original quest. It's difficult to lure users away until they've reached this (self-defined) point; before that, they will simply ignore distractions."
Up- and cross-selling techniques aren't just for e-commerce sites. For instance, UIE has started cross-selling on their own web site. Following each article is a section titled "For more usability information," which has links to courses and other material.
- The article Seductive Design for Web Sites
- July 18, 2002
See also: Tips and guidelines (95) Persuasive design (21)