TwLng is Buffer for Content with six main features:

1. Post content to Twitter that is longer than 140 characters 2. Add content to a queue for posting later. 3. Add content to a 'circle' for posting later. 4. Schedule post times using a calendar. 5. Follow users / favorite tweets based on a query from a calendar view. 6. Save drafts.

A circle is a queue where items are not popped - when the pointer reaches the end of the queue, it is reset back to the first element.