Osfoora has released a Twitter client for OS X on the Mac App Store.
Osfoora is a powerful Twitter client with a clean and intuitive user interface. You'll enjoy a wide set of powerful features such as Muting users, Read Later, Message Conversations, Multiple Accounts, and more.
FEATURE LIST: • Multiple accounts with multi-windows. • TweetMarker Support: Timeline syncing of reading position between different Twitter apps. • Inline picture thumbnails for popular services, e.g. Instapaper, Twitter, Yfrog, and more. • Mute users. • Mark Tweets belonging to specific users. • Attach multiple images/videos to tweets. • Image Services: Yfrog, TwitPic, Twitter, CloudApp, Imgly. • Set your own custom Image Upload end point (Must follow the TwitPic API and use JSON). • Video Services: TwitVid, Yfrog, TwitPic, CloudApp. • Read Later (Instapaper & Read It Later) with tweet attribution. • URL Shortening via CloudApp (Default is Twitter). • View/Subscribe to Twitter lists. • Access Twitter lists from user profiles (Lists they created, follow, or followed by) • Direct Messages with conversation view. • Search Twitter and view trends. • Flexible Font sizes (11pt - 20pt). • View users on Favstar, and Twitter websites. • Notifications via Growl and Dock Icon. • Edit your Twitter profile info. • Resizable Sidebar. • Robust Keyboard controls for navigation and popular tasks. • Other features such as Blocking users, Reporting Spam
You can purchase Osfoora for Twitter from the App Store for $4.99.