Bitcoin webcam classifieds site. Providers offering sex shows could pay small fees to post profiles/ contact info [eg. skype, gmail].
Customers could pay them directly in bitcoin and leave feedback on the service providers.
Payment of small incremental amounts x btc/min, charging for ads, and the use of feedback would discourage fraud.
The customers and providers could arrange for payment and communication independently of the site.
I am hoping that someone more entrepreneurial than myself will take this on.
i think it's a bad idea, it can change the behavour of morality ...