As of November 15, 2006 Microsoft will no longer accept new sign-ups for select Microsoft Online Small Business Services.
These services, previously marketed under the bCentral™ brand, include Appointment Manager, Banner Network Ads, Commerce Manager, Customer Manager, FastCounter Pro, List Builder, Sales Leads, SharePoint®, Submit it!, Traffic Builder, and Web Hosting Packages.
Matt points out that none of the Microsoft's other business web services offer a directory listing. So far there has been no official explanation or clarification of things to come. Chances are the directory has been temporarily withheld from new users for as all old users can still access the service. We might be looking at some experimentation or addition of features as complete withdrawal of service will be absurd.