I'm not going to suggest "subreddits" as a solution because eliminating mods in favor of ignoring/following makes moderation more decentralized and likely that Hubski will avoid the authoritarianism of reddit. In place of subreddits Hubski has "tags" and "following". This makes Hubski user-centric and thus a friendlier place than reddit. Reddit is largely the democratization of thought, not discussion for its own inherent value.
Back to my main point; sometimes I feel I can't share something because it may not interest all my followers. My followers interests all overlap with mine in different ways. This is because friendship is not a binary. People talk about different things in different contexts and with different groups of people.
Tags are also not a solution because anyone can spam a tag's stream and then we're back to subreddits with authoritarian mods. So interest/discussion-context clusters do not match users or tags.
So, how we need an algorithm that recommends posts to users through their overlap.
Where users' posts overlap there is formed a discrete interest. The transitive property can be used to connect these overlaps as they are actually the same interests.
The aim of link aggregators is to increase the concentration of interesting content. Skipping over uninteresting content can be done without a link aggregator. Following more people will quickly dilute the interestingness of links.
Self-censorship basically leads to a situation where you only share links that appear to the broadest-possible audience. Your followers might as well read top-ranked posts on r/all if you are going that route. Stumbling on fascinating things that I had no idea I could ever be interested in is why I read hubski. Besides, how can you know what I am or am not interested in? Your image of your followers is undoubtedly one-sided - I am certain that even people I know in real life have sides and interests I know nothing about, so how much more likely is it that you have no real idea what your followers truly like when we are talking about names behind a screen? With that in mind, it is pointless trying to fit your interests to some imaginary "broad" standard.