So this is a powerful new addition. ADSI relies on LDAP to do all of it's work. LDAP stands for Lightweight Directory Access Protocol. LDAP is a lightweight implementation of X.500. X.500 defined a standard way of organizing a directory service.
Directories organize information in a hierarchy, and provide a means for accessing that information.
Active Directory is based on LDAP, and one can query just about any information within AD via an ldap query. One can also modify information in AD via ldap. One need not be a windows client to use ldap. Vbscript is a lightweight version of Visual Basic. If you want to take advantage of WSH or ADSI, you'll have to know vbscript or another modern language.