A client is pushing to have Google Site Search set up.
Currently, their search is filterable (using dropdown) by category, tag, other taxonomies.
How can I implement this filtering with paid Google Site Search?
In Google Site search, you can set up Refinements ( Edit Search engine - > Search Features -> Refinements tab.
You can also set synonyms and promotions (so that particular pages will always appear at the top of specific search results pages).
The Google content is based on spidering though, so it won't understand back-end concepts such as 'tags' or 'categories' : you'll need to tag up your content using Google's labels system.
https://support.google.com/customsearch/answer/4542637?hl=en&ref_topic=4542213
I don't think this is a Wordpress-specific question.
