www.i2istudy.com is a free multilingual web service for studying and teaching foreign languages online. The main idea of the service is based on the principle of a “Time bank”: I teach. I am taught. For free. For every minute that I teach my mother tongue I am rewarded with a minute that I can use to learn a foreign language. This allows using the system free of charge.
i2istudy is the first specialized time-bank. The time bank operates with a special internal currency - minutes, which are part of gamification, motivating people to teach and to learn foreign languages. We hope that the idea is attractive.
In my opinion using "time" as the currency is very promising, attractive and understandable to users.