I was not the only one initially confused about OpenMeta and Mavericks tags. In the latest Macpowerusers, David Sparks asks Brett Terpstra what is the difference. It turns out OpenMeta and Mavericks tags are the same thing.
I figured this out as over the last few weeks my OpenMeta tasks have gradually and magically become Mavericks tags with no action on my part. Thus, several years I have spent tagging my reference files are not lost! Brett thinks in five years hierarchical folders will be all but gone from personal computers, replaced by tags. I am trying to prepare.