gistfile1.txt

class PostsController < ApplicationController
  def tag
    # Will return a list of items matching one or any tags passed to the controller, sorted, without duplicates
    @tag = params[:tag]
    @tag = @tag.split(",") if @tag =~ /,/
    @posts = Post.all(:conditions => { :tags => @tag }, :order => 'created_at desc' )
    ...
  end
end