App.net has a new API feature called Stream Marker.Dalton Caldwell:
Multiple times a day, I switch between my laptop and my phone. It’s frustrating that I have to ask myself “have I seen this post?” as I scroll through My Stream. Today we’re adding support for Stream Markers to the API. This will allows clients to sync where you are in your stream, global, and even in individual threads between clients.
This is fantastic. Tweetbot for iPhone, iPad, and Mac have used either Tweet Marker (now called Watermark) or iCloud to do something very similar in syncing where you've left off in a stream between apps/devices. This is something that has never been built into Twitter's API even though it seems like a no-brainer.
Great update to what is quickly becoming a far better API than Twitter's.