Because it is a concept of shared work. It is a new way to work. It is an alternative to the classic Business Center and of course to working from home.
Co-working as a new concept of common space, goes even beyond that. Co-working brings together ideas, skills, and values.
Co-working creates a personal and social network. It is really a co-working community. Thanks to this community, co-workers find through collaborative work all they need to develop their business, by sharing values and experiences to allow them to grow personally and professionally.