Even though LDAP has been around for almost a decade, it is still an evolving technology. As more companies deploy large-scale LDAP infrastructures, inadequacies and inefficiencies with LDAP arise. Also, as new technologies are developed, such as XML, vendors look for ways to make LDAP even more manageable.
Virtual List View (VLV) is an LDAP control that allows for a "virtual list box" graphical user interface in applications that need to display hundreds or even thousands of entries at a time. A good example of an application that can take advantage of this is the Microsoft Management Console (MMC). If you have ever tried to open a container that has several thousand objects in it with an MMC, you've experienced the delay before it returns with the message stating that it can only display a subset of the objects. VLV can alleviate this problem because the MMC will only retrieve a couple pages of entries, until the user scrolls up or down, and then retrieve more pages as necessary. VLV will be available in Windows .NET.
DSML stands for Directory Services Markup Language. It is an XML schema for defining directory content. XML is a good fit for representing data in a directory because it makes it very easy for XML-enabled applications to read and understand the data. While DSML has gained some acceptance in the industry, Microsoft has not announced any plans to interoperate or integrate with DSML. Microsoft has mentioned plans for some type of XML support in a future release of Active Directory, but nothing has been confirmed.