If you own an iPhone, chances are you have at least one Twitter client on it. And while everyday seems to bring new ones into the App Store, at the end of the day, Tweetie always seems to be the one that I go back to. TwitterFon, Twitterriffic and most recently, TweetDeck , all are worthy challengers, but I find each of them lacking in some regard. Usually, it's either speed or simplicity. Tweetie seems to be a perfect combination of the two. But a new app, Birdfeed , may be a little more perfect. When you first boot it up, you may think Birdfeed looks a little sparse. But there's a lot behind this simple design, it's just tucked away, so as not to clutter the main experience, as so many apps do. The main Birdfeed screen consists of your Twitter timeline, a button to load newer tweets, a button to compose a tweet, and a button to your account — that's it. Clicking on any tweet in your timeline will load it on its own screen and from there you can easily see that person's profile, reply to that tweet, favorite it or forward it (retweet it, post a link to it, or mail a link to it).