MG Siegler apparently got the scoop that Twitter is ending their Mac app:
Word is that Twitter made the call today: Twitter for Mac is done. They won’t kill it outright, but no further updates. Goodbye, old friend.
This isn’t a big surprise to most people. The app doesn’t support the new Retina MacBook Pro, and it’s lacking standard Twitter functionality introduced over the past year. What’s strange is that Apple partnered with the company to offer these services on the Mac, but Twitter is changing their own strategy at the same time. These goals could produce conflicts as Twitter seeks increased profitability.
Update: Gruber sez:
Worst part is, they may even have a retina-ready update ready to release — but they’re just going to keep it in their pocket out of spite. They want people to use the website.
Dick move, Twitter.