How do you reach women 18-25?
gstar: That's a very broad demographic - Can you slice finer?  The responses you have already are spot on, but they apply to a lot of other demographics too.If your app has a very broad market there's no point going after every 18-25/female because you can't afford to advertise to the whole demographic without some really really REALLY serious money.  You'll need to "pierce the zeitgeist" with something that captures imaginations to get the word out.Pierce the zeitgeist?  I do sound like a wanker, but you would probably need to step up from typical "viral" marketing techniques.  Don't go herding sheep with LEDs, step it up.  How?  No idea!