If you are a Twitter user, reloading the Twitter website happens often throughout the day. An application that makes this so much better is Twitterrific. It sells for $14.95, but if you don't mind seeing an ad every hour, you can get it for FREE. What is great about it is that it doesn't add any icon in the Dock or in the Command-Tab dialog. It can even automatically update your iChat, Adium or Skype status when you post a tweet. More info here on the developer's website.