The hiring of Anthony De Rosa from Reuters as editor-in-chief has given fresh buzz to Circa, which does "atomized" content, adding nuggets of info to continuing stories. I've been using the app for awhile and, while I like it, it's not yet got for me a compelling daily must-read. But the Circa team is onto something, something journalists should be paying attention too.
At this point, Circa doesn't do original reporting (although De Rosa suggests that is something he'd like to see), but it does have human editors who are rewriting and shifting down news to just the new bits readers on mobile devices need to know to "catch up." It's only a mobile app; there's no companion website or tablet app.
Give Circa a try; see what you think.