The Facebook had opened up the new featured Instant Articles, which articles are from participating load instantly when clicked. On iOS will coming soon within weeks.
Facebook Instant Articles is the rate at whatever they load when clicked. Unlike a regular URL click feature, the Instant Article is opening immediately, for all purposes and intents. Facebook said that it is 10 times faster than to a standard web browsing. Those on Android or iOS will know when an article is of the type based on a small lighting icon in the right corner.
Also, any links you received or sent in Facebook Messenger were opened in the mobile browser in default speed, unlike that opened in the Facebook app. This change only means the links will open in the same Messenger as they do in Facebook App directly.
It is similar to Google that they rolled out a mobile search app called Accelerated Mobile Pages. A variety of pages that load faster than average speed providing a better experience for readers via a mobile device.