I've had to drop five people in the past week because they don't understand that clicking the wheel doesn't mean "have an upvote" it means "I want to share this with everyone who thinks I share things that are worthwhile."
As far as impacting the quality of Hubksi as a site for users, this little confusion potentially detracts more than any strictly mechanical feature alone. It's a problem of educating the users on a mechanic, and I agree that the problem is real (and comparatively overlooked). Something as simple as a hover-over tool-tip with a little message on the hub wheel might do the trick. The problem is made worse by the fact that the wheel is identical for posts and comments, yet functionally it is completely different. In the comments it really does mean "Here, have an up vote". I love the look and universality of the wheel, but I don't like how users aren't treating it with the gravity it deserves on link side. There are many many many posts I enjoy very much that I don't share, simply because it's not content I particularly want to endorse to my followers. Maybe it's too niche, maybe it's too low-brow (and I'm just enjoying it guilty-pleasure style), or whatever. Do any of the new users understand this difference. Some probably. Most importantly, do the majority? Really, do the vast majority? It really should be the preponderance of users who clearly understand the main mechanic and its implications. I would hate to see a mechanic as central to Hubski's experience be as misunderstood or abused as Reddit's downvote.
It's not just new users that may tend to "share" too much or without enough restraint. I tend to share anything I consume so long as I found it interesting or learned something. mk on the other hand, like you, discriminates more. To each there own, I take absolutely no offense if someone I follow doesn't reciprocate. I share a lot.
Oh gosh, I am guilty of this. I thought it was an upvote! And a share, all at the same time. I didn't realize that I might be flooding people's feeds with some kind of kindness. Food for thought, and thank you for saying this.