SF in particular seems to be reviving the general concept of the boarding house[1]. It's interesting to think about the extent to which this trend might be related to high rents.
I lived in a big communal house for over a year, it's great and I'd recommend it to anyone. You get less distraction looking after things as there are scale advantages (eg only one person manages the cleaner), you share meals, you meet more new people and you get more stimulated with new ideas spread from conversation and peoples friends.
[1] http://www.sfgate.com/bayarea/article/Tech-entrepreneurs-rev...