Why would an article about Pluto being de-categorized as a planet generate significant sharing but low clickback rate? One common thread among content with high share rates but low clickbacks is a focus on esoteric topics that appeal only to a specific, highly educated minority. The fact that users share this content broadly despite the narrow target appeal suggests that the intent is more related to "personal branding" than curating helpful content. In other words, people like sharing content that identifies themselves with specific topics regardless of whether the recipients are actually interested in the topic. We call this type of behavior ego sharing.To translate from geek-speak, that means while people like reading about Kim Kardashian, they really don't want to admit it, including by sharing such articles. Instead, it's the so-called highbrow content such as science and politics that winds up on your Facebook (FB) or Twitter page or in your email box from family and friends. That's by design -- it makes the sender look good to the recipient, at least in the sender's mind.
Most people are reading People magazine online, not Popular Science. It's just that when you do read Popular Science, you're more likely to send a link to your social network, even though it's Kim Kardashian who's really on your mind.