* give you karma just for stopping by each day
* give you karma for upvoting other's posts
* give you profiles you could customize by trading in karma
* show you what your friends were upvoting and their Karma
* show you how close you were to attaining moderator status
* allow you to give one virtual gift per day to your favorite contributors
* have your karma decline if you don't stop by in a week
On HN, karma is earned much more rapidly by "skilled" users, even though to get a high karma you must use the site often. Taking this away would rob HN of its most valuable asset -- karma encourages "skilled" users to post insightful comments.
Video games should expand upon what we are capable of. Reward structures and timed events are fine to a degree, but Zynga goes too far. This kind of manipulation needs to be addressed, especially as games become more and more thoroughly integrated with our society.
I am not so sure it's that simple. The real challenge imho is to show how to get critical mass. Not to talk about how you optimize once you have it.
Does anyone know exactly the reason why farmville became popular, cause somehow I think it's not about those 8 principles?
This history of FarmVille implies it was better game mechanics than Farm Town, and Zynga's installed base, that lead to FarmVille's success: http://www.allfacebook.com/2010/01/farmville-history/.
I'd also hypothesize that Zynga grew because they:
* Had a working revenue model, so they could pay for advertising without burning cash. And being able to advertise in the place where someone plays is helpful for conversions.
* Built on a growing platform (i.e., Facebook)
I've been collecting some links to presentations and posts on designing for engagement. See the list here: http://www.kartme.com/phil/web-design
http://www.gamesbrief.com/2009/09/six-secrets-of-farmvilles-...
(HN and SO are similar in this way. You randomly get karma points, which mean people like you, and so you keep checking your threads page to see how much karma you've gotten since you've last looked. Same goes for replies. If there was no karma or no threads page, I bet HN wouldn't have any users.)
Oddly, it was at the point where I had more adventures in a day than I had time to use (and therefore started loosing them) was the point that I started to loose interest.