I'm still not even remotely sure what a Myspace app should even do (if we ignore the social networking part of it). If we look at Myspace as purely a place for music and look at it from that context... what should a Myspace app do exactly that the web browser doesn't allow us to do already? Should it upload music? Allow direct playing of your favorite bands bypassing the randomly broken flash player? What are you looking to do with it exactly? Also, no, I don't think you should be saying that devs shouldn't be coding for what they choose to. It's their time. If you want someone to work on Myspace stuff, either find people that want to do it or get Myspace to hire people to work on it.
The question with that is how long it takes. Tumblr take about 6 hours to publish from twitter and anything up to 3 days to publish from MMS (despite an immediate message receipt). I shall find out later this week, with any luck.