The killer application for the directory itself is the consistency and cost savings in having a single directory, vs. having many different and independent directories. Having something like Oblix's corporate directory, a white pages application, is a huge benefit in terms of cost savings to organizations. Over time, all of the ERP applications will migrate to use the corporate directory, the main directory of the organization to store their information about individuals. So the directory becomes the digital personae and any application that uses this information integrates into the directory. You said you see the directory as critical for e-commerce.
Electronic commerce involves relationships on the network.
Being able to know who the customers are is critical to make these applications work, because they have to be working off of a common image of the customer. Of course what will be the directory in a corporation is still seen as a moving target. It is hard to say what directory will be the winner. It's been out there for many years. I think Active Directory will have some strength, and IBM and Netscape will be major players.