sensorystore wrote: Can the administrator assign a list of keywords/tags to user profiles to assist in the search?
Actually Joomla does not have built-in tagging.
There are some tagging extensions on the JED you can look at - some can be extended to other components.
We do have a Joomla search plugin that you can use (part of the paid membership plans) to extend the Joomla searching to cover user profile data.