Twitterrific
iconfactory.com/software/twitterrific
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Twitterrific is a fun little application that lets you both read and publish posts or "tweets" to the Twitter community website. The application's user interface is clean, concise and designed to take up a minimum of real estate on your Mac's desktop.