Jakob Nielsen, Ph.D., is a retired principal and co-founder (with Dr. Donald A. Norman) of the Nielsen Norman Group. Jakob established the "discount usability engineering" movement for fast and cheap improvements of user interfaces and invented the heuristic evaluation method.
The Web is not a community: a huge impersonal city is a better metaphor. User-generated content (UGC) can be valuable (if edited), but chat rooms should be avoided because of participation inequality.
Loyal users who return to a site many times are more valuable than 'site tourists' who simply check out a few pages. Loyalty is built by fresh content, update notifications, and customization and other ways of rewarding repeat visits
Search is the primary interface to the Web for many users. Search should be global (not scoped to a subsite) and available from every page; booleans should be made intimidating since users usually use them wrong
CSS promotes site consistency and improved usability if linked (not embedded), centrally designed (not by page authors), and actively evangelized with example-rich style manuals. Respect user preferences.
Web project management impacts usability significantly. Mistakes include having site structure mirror your org chart, outsourcing to multiple agencies, generic links from offline collateral, and lack of strategic thinking.
Common conclusions about Yahoo, Wall St. Journal, Disney, The WELL, and Amazon.com are wrong: generalizing Web trends from popular examples featured in the press is dangerous; spectacular case studies are often outliers.
The telephone is a better metaphor than television for thinking about the Web and its potential: the Web is a 1-to-1, narrowcast, low bandwidth medium that is user-driven and where everybody can publish content.
Designing for the Web is different from traditional user interface design. Fundamentally, the designer gives up a lot of control to the user - get used to it: WYSIWYG is dead
How much better is it to be a *big* website? Large sites can use their own hyperlinks to drive even more traffic, but small sites generate more value through focused content and microtransactions. (Updated 2005.)
Examples from tech support calls show the immense difficulties novice users have in using the Internet: be prepared if you field apps intended for broad usage.
