If you're in college or maybe just got out and still regularly travel in a pack of close friends, you inevitably have those times where one person covers the share of the bill of another, or maybe one person pays the whole bill with the expectation that everyone will pay him/her back. Usually they don't pay you back, or they buy you a Three Musketeers bar as a make-good for your paying for the last pizza, which is not cool at all.

A new site concocted by three grad students at Carnegie Mellon, Buxfer, is attempting to fix this problem by putting all those IOUs online, allowing members of a group to tell each other to the penny how much they owe each other, and to allow for the back-forth of reciprocal paying while making sure it all comes out even.

Here's how it works, or at least how I think it works. The Buxfer guys can comment if I'm telling it wrong.

Let's say you and I and our friends Amir and George all go out to Siesta Mexicana and, when the bill comes, George as usual conveniently has no money on him. Amir and you decide to each throw in half of the $10 that George owes, feeling that George might pay you back despite his track record. (I know better and do not help George.) You suckers then jump on Buxfer and dutifully enter in the fact that George owes you $5 each.

A few days later, immediately after George gets off work bartending and is flush with tip cash, he meets up with Amir to see a local band pay for the ridiculously low price of $7. Amir has conveniently forgotten his wallet and gets George to pay the $7 ticket price. George jumps on Buxfer and makes it clear that he has paid his $5 obligation to Amir and now is actually owed $2. (You are still owed $5; you should know to catch George immediately after work if you want any hope of getting your money back.)

Buxfer has a few more features than I'm describing, but this seems the most likely scenario in which it would be useful.

It's an interesting idea, but I wonder if in the real world a group of friends or colleagues would use it religiously enough to make it work. Are you and I and George and Amir really going to jump on the site every time there's a transaction between us? Yeah we want our money, but do we then come off as jerks if we're constantly pointing to how much Buxfer says the other owes?

And, finally, Buxfer doesn't force someone like George to pay up if he simply never holds up his end of the financial bargain. George should feel guilty if he goes on Buxfer and sees he now owes his friends $167, but will he? If he did, he probably wouldn't have mooched so much in the first place and he certainly isn't going to go on Buxfer to remind him of his transgressions.

I suppose if you have a group that is committed to all being fair with one another, Buxfer will do the trick. But is a group of early 20s guys/girls going to be that committed to the fairness of it all? I can't speak for the current crop, but 10 years ago my group probably wouldn't have been.

If you have a group of upstanding citizens, however, give Buxfer a try. (By the way I wish they'd named it Buxter. Rolls off the tongue easier.)