As indicated above, networks of practice incorporate a range of informal, emergent networks, from communities of practice to electronic networks of practice. In line with Lave & Wenger's original work (1991), Brown & Duguid propose that communities of practice are a localized and specialized subset of networks of practice, typically consisting of strong ties linking individuals engaged in a shared practice who typically interact in face-to-face situations. At the opposite end of the spectrum are electronic networks of practice, which are often referred to as virtual or electronic communities and consisting of weak ties. In electronic networks of practice, individuals may never get to know one another or meet face-to-face, and they generally coordinate through means such as blogs, electronic mailing lists, or bulletin boards.