The MySpace platform can be viewed economically as a set of signals and incentives.
Regardless of MySpace's intentions, the net result of the way the platform is structured and all the policy actions taken thus far has been to reward spaminess and punish "good" apps.
MySpace authorities are clearly unhappy with this state of affairs since they continue to issue a series of new policy announcements meant to address these problems.
In fact, each successive policy announcement is a tacit acknowledgement that all the previous policies failed to solve the problems.
In terms of viewing things economically, something as simple as highlighting "recently popular" apps is an incentive to use any means to get quick spammy growth in order to be on that list over planning slow and steady growth. And the whole system is structured like this.
As far as I can see, the only incentive to following all the rules is to earn the staff's appreciation. While this is nice, it's not like extra free promotion.
Even the secrecy can be seen as contributing to the problem. There is a reason why trials are public or shops post photos of people caught shoplifting. The point is not to merely punish the offender, but to send clear signals to other people potentially contemplating doing the same.
If the crime was bank robbery, MySpace's justice would be to secretly make the robbers promise not to do it again, but let them keep all the money they stole. The criminals would then begin robbing savings and loans while MySpace turns a blind eye, claiming it's a gray area since technically savings and loans might not be banks.
Outside of arguing the intrinsic merits of many popular apps, everyone knows that most of them used very spammy tactics to acquire users, and everyone can see they actually benefited greatly with very little consequences.
It's like the broken window theory. All these apps are huge gaping broken windows sending a clear signal that this is a bad neighborhood, no one cares, and there is no hope. "Good" people will either leave, become victims, or turn to crime themselves in order to survive.
While I hope things change and will continue to develop apps for the time being, I actually don't expect much. I see MySpace dominated by a handful of large spammy app companies and making money off porno-like ads for web-cam girls. It's 99% of the way there now.