I explicitly said that it's not about keeping track of who's done whom a favour. I'd even say that each day, any old favours get reset and hidden from view.
Ah, my mistake. I have no idea how that managed to sneak onto the site. I'll get it changed soon.
@ollysb, @nodata: Sorry about that. I was honestly confused why people thought it was about keeping track and kept bringing it up when I'd said it wasn't. Now it all makes much more sense