Sure

I believe that if you want to do what dwanthny did, you first have to delete all your tags, otherwise they just get added on to the ones you already have. So a backup is in order.
But that leaves me with the problem, what about the books that I have personally tagged - the ones that may not be found by goodreads or other metadata tag gatherers.
Can't really go through all my books just selecting the ones I didn't tag for good reads to retag, so will end up loosing my tags on the ones I did myself.....
Think I'll stick with Genres for now, may even nest them. As for tags, I'm just going to go through and delete the ones with more than 10 tags, and let good reads retag those.
Then wait for inspiration.