Yahoo’s new home page design represents a fundamental shift in focus: The Web directory is no longer the main reason to visit. And this is troublesome.

To me, the most striking component of Yahoo’s new home page design is the relegation of the Web Site Directory to the lower left-hand quadrant of the page.

The change is a logical progression, but the home page is clearly restating Yahoo’s purpose. Now it’s somewhere to “shop, find, connect, organize, [and have] fun.” Note that “find” is second in this subtle mission statement, and Find’s options are all sales-oriented: careers, maps, people, personals, yellow pages.

Yahoo came to prominence as the pre-eminent Web directory. You wanted to find something, you found its link through Yahoo. The site then began to grow horizontally: You wanted to find something, you began to find it on Yahoo. As of today, the directory that defined the site is a secondary consideration.

I have used Yahoo since 1994 and I remain a fan of its services. As a long-time visitor, I can only wonder: How far can Yahoo stray from its initial mission before it begins to lose its usefulness? After all, I got to Yahoo Finance and Yahoo Weather because I used Yahoo’s listings.

I hope CEO Terry Semel’s long-term plan includes maintaining and updating the seminal Web directory. Without it, Yahoo may turn itself into just another bloated portal. And we know how the rest of the “portals” have fared.