I've lived in all sorts of tiny apartments in Japan and think they are very useful but only for very specific groups of people (students and single people). The

I've lived in all sorts of tiny apartments in Japan and think they are very useful but only for very specific groups of people (students and single people). The great thing about them is you can rent extremely cheap (I paid $450/month in a guest house where it was only the room and shared bathroom/kitchen/laundry etc). For a tiny 2 bedroom apartment I rented for $600/month but far away from the station. These are great for students and single people because you can meet others, it's very safe (generally), and very affordable. I don't know the new apartments going up in SF but if they made them extremely small units I'm sure they could fit a lot of people and be very reasonably priced (relatively).