We need a bartering/trading programming. In this website, instead of forcusing on items, , we focus on a service exchange. Simple process: 1. a boy posts his offer.(ex. I can teach you how to play baseball, so please teach me how to play soccer.) 2. a girl views his offer, and if she likes it, she pushs "offer" bottun, and send message/negotiation (ex.I can teach you socc...