Perhaps a good approach for this would be start by developing a website for people to host their profiles, preferences (do's, don't's, maybes etc), geographical coordinates where they usually can be found (home, work, clubs etc), a a live coordinate (like on those sites that already do it for less naughty purposes) and any other usefull data, and provide an API for searching and reading profiles, as well as editing your own, and sending messages to other members etc, ideally having the system be acessible both via the internet as well as by sending and receiving SMS's.