Here are a few ideas. The debit/credit terminology is too formal. Use something like "I owe" and "I am owed". I can see myself using this if it was more clos

Here are a few ideas. The debit/credit terminology is too formal. Use something like "I owe" and "I am owed". I can see myself using this if it was more closely focused on helping me track who I owe money. The confirmation system you have is too formal. How about this. I can record who I owe money, or record who owes me money. If I owe John money, I can optionally choose to send him a note (email) as a friendly reminder. Maybe integrate with Facebook so he can choose from a list of his friends. No need to remember an email address. I can also have it send me reminders to my facebook account or email.