Social networks in the 21st century include a wide array of partners. Most individuals report a few core ties (primarily family) and hundreds of peripheral ties. Weak ties differ from intimate ties in emotional quality, stability, density (i.e., who knows whom), and status hierarchies. Undoubtedly, close ties are essential for human survival. Yet peripheral ties may enhance life quality and allow people to flourish. Weak ties may serve (a) distinct functions from intimate ties (e.g., information, resources, novel behaviors, and diversion), (b) parallel functions to intimate ties (e.g., defining identity and positions within social hierarchies, helping when a family member is ill, providing a sense of familiarity), and (c) reciprocal influences between peripheral partners and family members (e.g., bioecological theory). Family science might benefit from investigating consequential strangers who pepper daily life.