This quote from Kim caught my eye:
"In my world, a metadirectory is one that holds metadata - not actual objects, but descriptions of objects and their locations in other physical directories."
LOL! This is *EXACTLY* the definition of a Virtual Directory. The virtual directory normally does not (with the exception of Radiant Logic which does both) hold actual data. It simply holds the metadata and knows where to get information. It presents information to client applications as if it held the data itself - hence the term "virtual".
It was unfortunate that as Kim said, folks didn't like the term "uberdirctory". If Zoomit had been called an uberdirectory, there might not have been as much confusion about the difference between Virtual Directory and Meta-Directory!
In the end, for me, virtual and meta/uber are 2 very different tools that solve different problems in enterprises. There is need for both. In Oracle's case, we chose not to build an uber-directory. Instead Oracle offers another variation on the meta-directory concept known as provisioning. This is where data is moved between the authoritative sources that already exist. Thus we have Oracle Identity Manager covering the provisioning side, and Oracle Virtual Directory covering the virtualization side.