That means Facebook was likely mulling over the impact it would have on the atmosphere of the news feed. Right now, most content shared to Facebook is relatively unique. Occasionally popular articles or memes get shared by lots of friends, but that’s a coincidence. When people do use the Share button on the web, they often give their own description of a link. But on mobile where typing is more of a pain, a Share button could encourage people to rapidly re-share link after link. That might make the feed seem repetitive and impersonal. Similar to the low-friction, easy-to-tap retweet button on Twitter mobile, Facebook users might Share instead of Liking.
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