Allow you to bulk add/remove tags directly on an ActiveRecord::Relation
If you are using Rails 3 Just put the .rb file it in your /lib folder
# Our ActiveRecord::Relation
clients = Client.where('created_at > ?', Time.now - 2.months)
# Our tags
tags_to_add = ['here','a','bunch','of','tags']
tags_to_remove = ['useless','now']
# Adding and removing tags
# (You can specify the tagging context as a second parameter)
clients.add_tags(tags_to_add).remove_tags(tags_to_add, 'jobs')
Works on MySQL databases