Together with the dawn of the interest graph and information overload, it's becoming obvious content curation is a major trend in social. Mathematical aggregators and algorithms can only do so much, but they are no match against the collective effort of millions of people. This fact helped services supporting social curation to emerge everywhere, in different shapes. Twitter, Reddit, Digg, Delicious, StumbleUpon, Tumblr, Pinterest, even Facebook and Google search are offering you a filtered experience of the Web, an experience that is determined more or less by other people who share your interests. Social curation at its best.
I love these services, but as I've become a heavy user, I also started wondering, if they can work on the long run using only positive actions. Likes, upvotes, diggs, +1s, retweets, reblogs. All used to amplify, not suppress. But what if I want to prevent something from spreading, wouldn't that be curation too? Wouldn't that be a statement that would suggest the creator / curator to try harder? Another problem: how can you prevent an organized group of people (or people with multiple accounts) who are all trying to push something forward, from ruining the experience for others, without the ability to quiet them down?
I remember when Digg and Reddit were in the same league. They both used upvotes and downvotes and had similar traffic and the number of upvotes on the front page. A few years later, Digg was experimenting with becoming more Twitter-like, canceling the downvotes and introducing following. They failed miserably, but also because Digg front page was supposedly controlled by the power users. The ugly side-effect of content curation without proper goals and (crowdsourced) control. But things like that happen, and there's a good reason we probably won't see the Facebook Dislike button anytime soon.
Curation services, constructed around recommendation (Digg, Reddit, StumbleUpon), recognized the need for negative action and allow (anonymous) dislikes. On the other hand, those services, that are built more around social (Facebook, Twitter, Google+), can't afford to have them without causing a social problem, creating Enemies from Friends.
But there's always an option. An option that is sadly way more drastic than a dislike could ever be. Unfollow. Unfriend. Unsubscribe. Report. Remove yourself from something. An action that not only discontinues the information flow, but also discredits the creator / curator in a way. And it may as well be the ultimate dislike. Like it or unlike it, content curation without the negative action can't exist.