Could we get a command that explains how to use the trade system? I don't think the system is inherently intuitive if you are trying to trade mcmmo levels and have tried 3 times, gotten someone to explain how to do it, and still not be able to trade.
When you can't figure something out, even with the help of others, then something is inherently unwieldy about the system. Especially when the trade window shows you offering negative exp...