For some of the biggest and most considered products and services, the decision to buy doesn’t always come down to a solo customer.
From finance and utilities, to travel, household goods, and entertainment, we often buy (and use) products and services as a couple, family unit, or group of friends.
Why then do many of the online systems we use treat customers as solo decision-makers, tying customer accounts to an individual email address and neglecting (or even discouraging) sharing and collaboration?
http://econsultancy.com/defining-ux-best-practice-for-shared-customer-experiences/