The article is discussing "share on [Facebook,Twitter,etc...]" type buttons on websites, not share via [OS functionality or other native app] buttons inside native apps.
That said, I'm curious as to why someone with enough technical sophistication to be posting on HN browses Amazon with a native mobile app instead of a web browser.
That said, I'm curious as to why someone with enough technical sophistication to be posting on HN browses Amazon with a native mobile app instead of a web browser.