IFTTT via an email newsletter that went out a few minutes ago:
In recent weeks, Twitter announced policy changes* that will affect how applications and users like yourself can interact with Twitter’s data. As a result of these changes, on September 27th we will be removing all Twitter Triggers, disabling your ability to push tweets to places like email, Evernote and Facebook. All Personal and Shared Recipes using a Twitter Trigger will also be removed. Recipes using Twitter Actions and your ability to post new tweets via IFTTT will continue to work just fine.
Twitter won’t be happy until the only way you’re interacting with their service is via their website or 1st party apps.
For now, only Twitter triggers is getting canned. Sending something to Twitter remains. For those relying on IFTTT to simultaneously post to app.net with a Twitter post, create a new recipe that reads posts from app.net and forwards them to Twitter.