Grackle68k is a twitter client for early Macintoshes running System 6 through OS9.
Download: Version 0.0.9
What's New in Version 0.0.9?
Not a lot, but it's less proof-of-concept and more user-friendly. You can hit [enter] instead of clicking "ok". That's nice. Also, if you use resedit to put your username and password in the obvious STR resource, you won't have to enter it when you start the program. It would be nice if you didn't have to use ResEdit, but why not open ResEdit and reminisce anyway?
Known Bugs & Things to Fix