A horrible script for Stack Overflow Growl notifications

so.rb

require 'nokogiri'
require 'open-uri'
require 'json/pure'
require 'ruby-growl'

class StackOverflowNotifier

  def initialize(*args)
    @data = if File.exists? "data.json"
      JSON.parse(File.read("data.json"))
    else
      {}
    end

    parse("http://stackoverflow.com/feeds/tag?tagnames=#{args.join("+")}&sort=newest")

    write
  end

  def parse(page)
    page = Nokogiri::XML(open(page))
    entries = page.css("entry")
    entries.each do |entry|
      url = entry.css("id").text
      title = entry.css("title").text
      notify(url, title) unless @data[url]
    end 
  end

  def write
    File.open("data.json", "w") { |f| f.write(@data.to_json) }
  end

  def notify(url, title)
    g = Growl.new("localhost", "ruby-growl", ["Stack Overflow Notification"])
    g.notify("Stack Overflow Notification", title, url)
    `open #{url}`
    @data[url] = title
  end

end    

File.open("so.log", "a") { |f| f.puts "Running on #{Time.now}" }
StackOverflowNotifier.new "ruby", "ruby-on-rails", "ruby-on-rails-3", "javascript"