The impetus for the group home or collective they hope to form is less about finances — though it is true that pooling resources yields better real estate — and more about community building. Indeed, Ms. Berger and others seem to share the ideals of the old-fashioned communes of yore, except that their groups are tiny, urban-centric and linked to outside interests like fixing bikes or, here in New York City, membership in the Park Slope food co-op. And like communes, many collectives give themselves names: The House of Tiny Egos (a name that’s decidedly more evocative than, say, Findhorn, that of the hoary Scottish commune) is a five-person collective in a century-old brick bungalow in Bed-Stuy. Not only do they aim to remain of the world, they hope for a convenient location, one that’s near all the major subway stops.Are their numbers surging? Hard to tell, though people who study more traditional “intentional communities” — that is, any group of individuals living together with shared values, as in a commune or collective — say that they are demonstrably on the rise. Laird Schaub, executive secretary of the Fellowship for Intentional Community, said his nonprofit’s database has swelled from 614 communities in 2005 to more than 1,300 this year.