Structured discovery is a set of steps by which a user interacts with an application to discover something new and, if the stars are aligned, something valuable. Even the most immersive worlds of modern 3D games have their rules. Levels generated on the fly still obey some designer’s intent for the user to see things in a certain order and at a certain pace. A Twitter user three degrees of separation away will take 3*a+b mouse clicks to find, assuming you click here, scroll all the way down here, click there and so on. You get the point.
Think about a kind of “value map” or “reward map” for your application. Where is the value concentrated for your users? What motivates the users to jump through the hoops and obey all the rules and how many hoops can they tolerate before getting frustrated and leaving? Is it the process of slashing monsters or the progress to the next level that is most rewarding?
To put it another way, social network-like applications (Facebook, Foursquare, Twitter, and eventually JustLiked) have a lot to learn from the way best computer and board games are set up and the reasons they are set up that way. It’s all about objectives, incentives, and the steps in between. Game designers have already done the heavy lifting of building rewarding experiences for users, lowering frustration, increasing retention and carefully measuring distances between adjacent breadcrumbs (a.k.a. structuring discovery to make it universally appealing).
I am not saying social networks should all have game incentives baked in. Instead web app designers should recognize before them the same class of issues, e.g. overcoming user fatigue, keeping users coming back for more, and rewarding them just enough, which have been successfully addressed in games millions of people play ever day. Although not everything can be transplanted, I still think the analogy is appropriate.