To sleep.fm guys: not trying to offend, I genuinely think it's a bad idea.
To those who were in elementary school when Seinfeld was on: damn kids:-)
Like Redux, they would be helping their users get laid.
It could be useful if they streamlined it and marketed it without the corn :P
"Out of all the ideas you could build for this platform, this one is quite possibly the worst idea ever."
Sleep.fm probably didn't work on android :P
And like youtube there could be top rated wakeup messages and bedtime stories. It could be a passive voicetwitter that helps you in and out of your day.
Are you one of the founders?
You have the wrong attitude if you are only focused on what investors want.
EDIT: To answer your other question, I am not a co-founder, but looking at pure numbers they are doing better than my last two trials and those of a lot of us.