Yes, this works without any IT, if you trust him. Until he defaults and you have nothing to show in the court.

What I mean is this: 

I run the local store and a local comes in to buy the usual bread and milk every fee days. Today he comes in but the internet us down. He takes the bread and milk and I write on the blackboard behind the counter that he owes me money for these items. Next time I expect him to pay.

This isn't a communist utopia. It's localized credit.

That's some communist utopia. I know many people around me, but won't lend money to anyone.