Interesting thought. I've seen IOUs between developers and designers go bad sometimes though. Different people quantify things differently. I gave a dev friend three hours of tutorial on photoshop, and later he complained about me asking him for the time back, even though that was the whole point – so I could learn some programming. Then it became an issue of "tracking hours too closely" and we never really connected again.
I'm not saying it can't work, but it does get hairy with "social debt" and how different people interpret that. "My time as a developer is worth $150 an hour, and yours is worth $75 an hour, so the time I put in is worth twice yours." I heard one dev tell a designer that once.
You held your friends' unwillingness to return a favor against him and destroyed a friendship?
I'm sorry, but that's just immature, and it's possible that by disconnecting from you your 'friend' made a wise move. It's just three hours of time; your friend is a human being. I interpret social debt as a proxy to good manners, and nothing more. I freely <strike>loan</strike>gift money, time, and stuff to my friends and relatives, and I make a point to forget about it ASAP. It's just stuff! It makes me sad when people let transient stuff like 3 hours, a broken borrowed tool, or a $20 IOU get in the way of your relationships. If your friend hesitates to call you because they expect that you'll ask about "when are you going to teach me that/return this/refund that" then there's something wrong. Life is about people, not time you've spent in the past, the stuff you own, or the money in your wallet. Do something kind today.
A system to correlate helpfulness should be implemented to prevent help vampires[1] from draining the site's users, but it shouldn't be featured too prominently. Perhaps anonymous exit surveys could be used to determine reputation, visible on a users' profile? Something like "User participated in X projects and received an average rating of Y/5 for contributions", and users with extremely low ratings could get "You've been warned" annotations.
The system probably doesn't even need to specify whether the user volunteered help or requested help for the project; this tool will only thrive if there are plenty of projects to do, and it can be hard to come up with good ones. Unless, of course, I'm misinterpreting this and the project authors don't participate in the effort, which could make this difficult.
I don't see this as much as an IOU exchange center as an opportunity to work on stuff I love to do with people I haven't yet connected with.
I have actually written all the projects I have had through and asked for their feedback on a number of things. Among others quality, whether the project owner answered all the pledges etc.
We interpret it pretty loosely. Don't get too hung up on the terminology :)
I have had 200 projects through and 600 pledges of help. Most of those I have asked have been positive. I am simply connecting people, the rest is up to them.
I'm not saying it can't work, but it does get hairy with "social debt" and how different people interpret that. "My time as a developer is worth $150 an hour, and yours is worth $75 an hour, so the time I put in is worth twice yours." I heard one dev tell a designer that once.