he main differentiator between this project and Facebook's is that Google and Twitter wouldn't host content themselves; rather, clicking on a link would bring open up a cached "snapshot" of the webpage. For users, it should be functionally similar to Facebook Instant Articles, but publishers should be happy to host their own content.
For many web publishers, Facebook is often the greatest driver of traffic to a website, which is great, but publishers fear becoming beholden to the whims of a third party. New York Times columnist David Carr summed up these fears eloquently in his October 2014 report on Facebook developing Instant Articles:
"The Facebook dog is loose, and he’s acting more friendly than hungry. But everyone knows that if the dog is big enough, he can lick you to death as well."
When Facebook Instant Articles rolled up this past May, Mashable's Jason Abbruzzese and Jenni Ryall said it was a "damned if they do, damned if they don't situation," meaning publishers could lose out if they didn't jump on the Facebook bandwagon, but they could lose if they become too reliant on Facebook for traffic.
Apple also has a new news platform debuting with iOS 9, simply called News, which hosts publisher content within the app. As Re/Code notes, both Apple and Facebook allow publishers to keep 100% of the revenue of ads they place on their content.
It seems that Google and Twitter want to avoid raising those fears, while still offering a faster mobile experience. It sounds like a win-win for all involved, but it's too early to make a definitive declaration