This module is a preliminary work.
Almost no documentation, and no user help.
Module's purpose must be made more clear.
Although the feature of having bulk auto-tagging seems attractive at a first glance, crowd-sourced tagging as done in social networks is much more accurate.
Developing big taxonomies takes tons of time, so this module didn't have lots of testing.
I didn't dig into the code, but you can see the module's UI when you try to save a node. From what I have seen, it only autotags upon saving the node.